15 Free Online Courses for High School Students

School gives you a foundation, but it doesn’t always cover the subjects you’re most excited about. It’s frustrating to discover an interest, then realize there isn’t a course for it, or that you’ll have to wait years before you can take one. That’s where free online courses for high school students come in, making it possible to explore topics like behavioral economics, astrophysics, game design, philosophy, and machine learning whenever you’re ready.

Imagine spending a few hours each week learning computer science from university professors, exploring neuroscience, studying business, or diving into climate science, literature, math, or law. You’ll get a feel for how college classes actually work while figuring out which subjects keep pulling you back.

Because these courses are free, there’s also room to explore without much risk. You can investigate new interests, change direction if something doesn’t suit you, and gradually build a clearer picture of the subjects you’d like to pursue in the future.

Why should you choose a free online course in high school?

One of the biggest advantages is that you get to replace assumptions with experience. It’s easy to think you’re interested in psychology because you enjoy reading about human behavior, or that computer science is the right major because you like technology. Spending a few weeks working through university-level material often tells a very different story. 

Free online courses also give you access to ideas that rarely fit into a school timetable. You can explore everything from behavioral economics and astrophysics to game theory, architecture, public health, or artificial intelligence without waiting for college. Many are taught by university professors or researchers, so you’re learning how people in the field actually approach problems rather than relying on simplified textbook explanations.

To help you get started, we’ve compiled a list of 15 free online courses for high school students!

For related options, consider summer programs for high school students.

Key takeaways

• MIT OpenCourseWare’s Thermodynamics and Climate Change course is completely free and open access, requiring proficiency in single-variable calculus and basic programming.
• Immerse Education’s Online Research Programme offers 1:1 or small-group mentorship from tutors at Oxford, Cambridge, and Ivy League universities, open to students aged 13 to 18 worldwide, with an opportunity to publish research and present at the Immerse Online Symposium.
• CS50, Harvard’s flagship computer science course, is free to audit and covers algorithms, data structures, and multiple programming languages including Python, C, and JavaScript.
• Virtual NSLI-Y is a completely free 10-week language program admitting approximately 10 students per class, teaching Arabic, Mandarin, or Russian to absolute beginners.
• The CDC Museum Public Health Academy Online Summer Course is free and admits approximately 75 students, taught directly by CDC educators covering epidemiology and disease surveillance.
• Stanford Code in Place is a free six-week programming course based on Stanford’s CS106A curriculum, led by volunteer instructors during weekly virtual discussion sections.
• HarvardX’s Justice course is free to audit and explores moral and political philosophy through the ideas of Aristotle, Kant, Mill, and Rawls over approximately 12 weeks.
• Nearly every course in this list is free to audit, with optional paid certificates ranging from $50 for Stanford’s Principles of Economics to $219 for CS50’s verified certificate.

15 Free Online Courses for High School Students

1. MIT OpenCourseWare – Thermodynamics and Climate Change

Location: Online
Cost: Free
Acceptance Rate/Cohort Size: Open enrollment
Program Dates: Self-paced
Application Deadline: None
Eligibility: High school students worldwide with proficiency in single-variable calculus and basic programming experience

This self-paced MIT OpenCourseWare course explores the principles of thermodynamics and how they apply to climate science. You’ll study topics such as energy transfer, heat, entropy, and the physical processes that influence Earth’s climate system using lecture notes, assignments, and other course materials from MIT. 

As you work through the content, you’ll strengthen your understanding of the scientific concepts behind climate change while applying mathematical and computational reasoning. Because the course is based on actual MIT coursework, you’ll experience university-level material while learning at your own pace. 

Why it stands out: It provides free access to authentic MIT course materials, allowing you to study thermodynamics and climate science at a university level.

2. Immerse Education’s Online Summer School

Location: Fully remote
Cost: Varies; summer school scholarship available through our bursary programme, and multiple competitions free for students to enter
Acceptance Rate/Cohort Size: Selective; an average of 7 participants per class
Program Dates: Flexible; multiple cohorts throughout the year
Application Deadline: Rolling admissions
Eligibility: Students ages 13-18 (accredited options require students to be 14+); open to international students

The Online Research Programme allows you to investigate an academic topic alongside tutors from Oxford, Cambridge, and Ivy League universities. You’ll work independently or in a small group to develop a research question, conduct in-depth analysis, and produce a university-style research paper in your chosen subject. With more than 20 subject areas available, including AI, psychology, economics, chemistry, philosophy, and computer science, you can tailor the experience to your interests. 

Throughout the program, you’ll receive personalized mentorship while building the research, writing, and critical thinking skills expected in higher education. You’ll also receive written feedback, have the opportunity to publish your work, and present your research at the Immerse Online Symposium.

Why it stands out: It combines individualized mentorship with an authentic research experience and opportunities to showcase your work.

3. MIT OpenCourseWare – Introduction to Statistical Physics

Location: Online
Cost: Free
Acceptance Rate/Cohort Size: Open enrollment
Program Dates: Self-paced
Application Deadline: None
Eligibility: High school students worldwide with proficiency in algebra, trigonometry, basic differentiation/integration (calculus), and introductory physics (Newton’s laws of motion, 1D kinematics, and conservation of energy)

This MIT OpenCourseWare course introduces statistical physics by examining how microscopic particles give rise to the large-scale behavior of matter and energy. You’ll work through lecture notes, problem sets, and supplementary materials that explain concepts such as probability, entropy, thermal equilibrium, and statistical mechanics. 

The course encourages independent learning while helping you develop the mathematical reasoning needed to understand complex physical systems. You’ll study the same instructional materials used in an MIT course, giving you exposure to university-level physics at no cost. 

Why it stands out: It offers free access to rigorous MIT coursework covering one of the core subjects in advanced physics.

4. MIT OpenCourseWare – Introduction to Oscillations and Waves

Location: Online
Cost: Free
Acceptance Rate/Cohort Size: Open enrollment
Program Dates: Self-paced
Application Deadline: None
Eligibility: High school students with proficiency in algebra, trigonometry, matrix math, analytic geometry, basic calculus, and basic physics (Newton’s laws, 1D kinematics, projectile motion, and conservation of energy/momentum); international students are welcome to apply

This self-paced course explores the physics of oscillations and wave motion through structured lecture notes, assignments, and problem sets developed by MIT faculty. You’ll learn about harmonic motion, resonance, wave propagation, and related concepts that form the foundation of many topics in physics and engineering. 

As you progress through the material, you’ll strengthen both your conceptual understanding and quantitative problem-solving skills. The course mirrors the content of an undergraduate MIT class while allowing you to learn independently at your own pace. It’s especially useful if you’re preparing for advanced study in mechanics, electricity and magnetism, optics, or engineering.

Why it stands out: It provides a strong foundation in wave phenomena using free university-level materials from MIT.

5. StanfordOnline – Principles of Economics

Location: Online
Cost: Free to audit; an optional verified certificate is available for $50
Acceptance Rate/Cohort Size: Open enrollment
Program Dates: Self-paced (approximately 10 weeks, 5-10 hours per week)
Application Deadline: Rolling
Eligibility: Open to all learners

This introductory economics course covers the core ideas behind microeconomics and macroeconomics through video lectures, quizzes, readings, and practical exercises. You’ll examine concepts such as supply and demand, market structures, inflation, unemployment, consumer behavior, and government policy while exploring how economic principles apply to everyday decisions. 

The self-paced format allows you to progress through the material according to your own schedule. Taught by Harvard faculty, the course provides a solid academic introduction to economics while remaining accessible to students with no prior background in the subject. You can complete the entire course for free, with the option to purchase a verified certificate if you’d like formal recognition of your work.

Why it stands out: It offers a comprehensive introduction to economics through free online instruction from Stanford faculty.

6. BerkeleyX: Entrepreneurship For All (Part I): The UC Berkeley Startup Guide for Students by Silicon Valley Insiders

Location: Online
Cost: Free to audit; an optional verified certificate is available for $199 (financial aid available)
Acceptance Rate/Cohort Size: Open enrollment
Program Dates: Self-paced
Application Deadline: Rolling
Eligibility: Open to all learners

This self-paced BerkeleyX course introduces you to the fundamentals of entrepreneurship, guiding you through the process of turning an idea into a viable startup. You’ll explore topics such as identifying market opportunities, validating business ideas, developing business models, and creating effective pitches through video lectures, readings, projects, and interactive activities. 

Drawing on insights from entrepreneurs and industry professionals in Silicon Valley, the course emphasizes practical strategies that founders use to launch and grow new ventures. You’ll gain a structured understanding of the startup lifecycle while applying entrepreneurial thinking to real-world business challenges. The course is free to complete, making it an accessible way to explore entrepreneurship before committing to more advanced business programs.

Why it stands out: It provides a practical introduction to entrepreneurship using insights from Silicon Valley experts, with free access to the complete course content.

7. CS50: Introduction to Computer Science

Location: Online
Cost: Free to audit; an optional verified certificate is available for $219
Acceptance Rate/Cohort Size: Open enrollment
Program Dates: Self-paced (approximately 12 weeks, 10-20 hours per week)
Application Deadline: Rolling
Eligibility: Open to all learners with or without prior programming experience

As one of the most well-known free online courses for high school students, CS50 is Harvard University’s flagship introductory computer science course, designed for both beginners and students with previous coding experience. Throughout the course, you’ll learn core computer science concepts, including algorithms, data structures, abstraction, software engineering, and web development, while completing hands-on programming assignments.

You’ll also gain experience with programming languages such as C, Python, SQL, JavaScript, HTML, and CSS by solving real-world problems inspired by fields like biology, cryptography, finance, and gaming. The course concludes with a final programming project that allows you to apply what you’ve learned while building a portfolio-worthy piece of work. 

Why it stands out: It provides a rigorous introduction to computer science using Harvard’s renowned CS50 curriculum, with free access to course materials for learners worldwide.

8. Google AI Professional Certificate

Location: Online
Cost: Included with Coursera Plus; financial aid available through Coursera
Acceptance Rate/Cohort Size: Open enrollment
Program Dates: Self-paced (approximately 10-11 hours total)
Application Deadline: Rolling
Eligibility: Beginner-friendly; no prior AI experience required; open for international students

This beginner-friendly certificate introduces you to practical applications of artificial intelligence across research, communication, planning, content creation, data analysis, and app development. Through seven short courses, you’ll learn how to write effective prompts, use generative AI responsibly, analyze information, and build AI-powered solutions. The program includes more than 20 hands-on activities that help you apply AI tools to realistic workplace scenarios while developing a portfolio of practical projects. 

The curriculum focuses on AI literacy and real-world problem-solving, making it accessible for students who want to understand how artificial intelligence is used across different industries. Upon completion, you’ll earn a professional certificate from Google that you can add to your resume or LinkedIn profile.

Why it stands out: It offers practical, hands-on AI training designed by Google, covering real-world applications of generative AI across multiple disciplines.

9. Yale University – The Science of Well-Being

Location: Online
Cost: Free to audit; optional certificate available through Coursera Plus or paid enrollment
Acceptance Rate/Cohort Size: Open enrollment
Program Dates: Self-paced (approximately 1 week, 10 hours total)
Application Deadline: Rolling
Eligibility: Open to all learners, including high school students

This popular online course explores the psychology of happiness and well-being through research-backed lessons led by Yale professor Laurie Santos. You’ll examine common misconceptions about happiness, learn how habits influence well-being, and complete practical exercises designed to help you build healthier routines. The course combines short video lectures, quizzes, and reflective activities that encourage you to apply psychological concepts to your own life. 

Rather than focusing only on theory, the course challenges you to practice evidence-based strategies that can improve resilience, mindfulness, and everyday decision-making. Its accessible format makes it a good choice for high school students who want an introduction to psychology while developing practical life skills they can use beyond the classroom.

Why it stands out: It combines Yale’s research on positive psychology with practical exercises that help students build healthier habits and improve overall well-being.

10. Stanford Online – Your Body in the World: Adapting to Your Next Big Adventure

Location: Online
Cost: Free to audit; optional paid certificate available through edX
Acceptance Rate/Cohort Size: Open enrollment
Program Dates: Self-paced
Application Deadline: Rolling
Eligibility: Open to all learners; a basic understanding of human physiology is helpful but not required

This self-paced Stanford course introduces you to environmental physiology by exploring how the human body responds to different physical conditions such as extreme heat, cold, altitude, stress, aging, and changes in pressure. Through story-driven lessons, expert interviews, and real-world demonstrations, you’ll learn the science behind the body’s adaptive responses while following instructors on research-focused adventures across locations including Stanford, MIT, and Pikes Peak. 

The course combines engaging videos with supporting learning materials to explain complex physiological concepts in an accessible way. Rather than relying solely on lectures, the course uses hands-on demonstrations and storytelling to help you understand how physiology applies to real-world environments and challenges.

Why it stands out: It combines interactive storytelling with university-level physiology, helping you understand how the human body adapts to challenging environments through real-world demonstrations and scientific research.

11. Virtual NSLI-Y

Location: Online
Cost: Free
Acceptance Rate/Cohort Size: Overall acceptance rate not specified; approximately 10 students per class
Program Dates: September – November
Application Deadline: May – June (tentatively)
Eligibility: U.S. high school students ages 15-18 who are absolute beginners and have no prior study or experience in the selected target language

Virtual NSLI-Y is a 10-week online language program where you’ll study beginner-level Arabic, Mandarin, or Russian through live classes taught by experienced instructors. You’ll participate in conversation practice, role-playing activities, cultural workshops, guest speaker sessions, and virtual tours while building practical communication skills and learning about the cultures where each language is spoken. 

The program also includes homework, assessments, and optional community events that give you additional opportunities to practice outside of class. The small class format encourages regular interaction with instructors and classmates throughout the program. It’s a good choice if you’re interested in languages, international relations, or global studies and want to begin learning a less commonly taught language.

Why it stands out: It combines live language instruction with cultural immersion in small classes, giving you a structured introduction to Arabic, Mandarin, or Russian at no cost.

12. CDC Museum Public Health Academy Online Summer Course

Location: Online
Cost: Free
Acceptance Rate/Cohort Size: Approximately 75 students (tentatively)
Program Dates: June 9th – 13th (tentatively)
Application Deadline: March
Eligibility: Rising high school juniors or seniors from around the world who are at least 16 years old

This online course introduces you to the fundamentals of public health through independent lessons and live sessions led by CDC educators and subject matter experts. You’ll study topics including epidemiology, disease surveillance, environmental health, chronic disease prevention, and global health while completing case studies, discussions, quizzes, and data interpretation activities. 

Throughout the week, you’ll learn how public health professionals investigate health challenges and communicate scientific findings to different audiences. The combination of self-paced coursework and live instruction provides a structured introduction to the field. It’s a good choice if you’re interested in medicine, biology, public health, or health policy.

Why it stands out: It allows you to learn directly from CDC experts while exploring how public health professionals investigate and respond to real-world health challenges.

13. Stanford Code in Place

Location: Online
Cost: Free
Acceptance Rate/Cohort Size: Not specified
Program Dates: April (approximately six weeks)
Application Deadline: Spring (tentatively)
Eligibility: Open to all learners

Stanford Code in Place is a six-week online programming course based on the university’s introductory CS106A curriculum. You’ll learn Python fundamentals such as variables, loops, conditionals, functions, and data structures through coding exercises, interactive lessons, and hands-on projects. 

Weekly virtual discussion sections led by volunteer instructors give you opportunities to ask questions, receive guidance, and collaborate with other learners as you build your programming skills. The course is designed to mirror the experience of Stanford’s introductory computer science class while remaining accessible to beginners.

Why it stands out: It adapts Stanford’s flagship introductory computer science curriculum into a free, instructor-supported online course for learners around the world.

14. HarvardX – Justice

Location: Online via edX
Cost: Free to audit; an optional verified certificate is available for $209
Acceptance Rate/Cohort Size: Open enrollment
Program Dates: Self-paced (approximately 12 weeks)
Application Deadline: Rolling
Eligibility: Open to all learners

HarvardX: Justice explores moral and political philosophy through lectures, readings, and discussions centered on real-world ethical and public policy questions. You’ll examine topics such as equality, human rights, markets, affirmative action, and criminal justice while studying the ideas of influential philosophers, including Aristotle, Kant, Mill, and Rawls. 

As you work through case studies and debates, you’ll strengthen your ability to evaluate arguments, analyze evidence, and think critically about complex social issues. The self-paced format allows you to complete the course according to your own schedule. 

Why it stands out: It introduces you to one of Harvard’s most well-known humanities courses while helping you develop critical thinking and analytical reasoning skills.

15. MIT OpenCourseWare – Introduction to Architecture & Environmental Design

Location: Online
Cost: Free
Acceptance Rate/Cohort Size: Open enrollment
Program Dates: Self-paced
Application Deadline: None
Eligibility: Open to all learners

This MIT OpenCourseWare course introduces the foundations of architecture and environmental design through lectures, readings, and design assignments developed for MIT students. You’ll explore topics such as urbanism, spatial representation, design methodologies, and the relationship between architecture and the built environment while strengthening your analytical and creative thinking skills. 

As you complete the coursework, you’ll examine how architects approach design challenges and evaluate the impact of design decisions on cities and communities. Because the course is based on the actual MIT curriculum, you’ll experience university-level material while learning independently at your own pace. 

Why it stands out: It provides free access to authentic MIT course materials that introduce the core principles of architecture and environmental design.

Frequently asked questions: Free online courses for high school students

Are free online courses for high school students actually free?

Yes, all of the core coursework in this list is free to access, including MIT OpenCourseWare’s physics and climate courses, CS50, and HarvardX’s Justice. Several courses offer an optional paid certificate for those who want formal recognition, ranging from $50 for Stanford’s Principles of Economics to $219 for CS50. Immerse Education’s Online Research Programme is also free, with selected scholarship places available through its bursary programme.

Do free online courses award college credit?

No, none of the courses in this list award transferable college credit. Most instead provide an optional verified certificate, like those available through CS50, HarvardX’s Justice, or Google’s AI Professional Certificate, which you can add to a resume or LinkedIn profile. If earning transferable credit is your priority, look instead toward paid, accredited pre-college programs rather than these free enrichment courses.

What is the difference between a self-paced course and a live cohort-based course?

Self-paced courses, like MIT OpenCourseWare’s physics offerings or Stanford’s Principles of Economics, let you move through recorded lectures and assignments entirely on your own schedule. Live cohort-based courses, like Virtual NSLI-Y or Stanford Code in Place, instead involve scheduled classes or discussion sections with instructors and other students. If you want maximum flexibility, a self-paced course fits better; if you want structured interaction and accountability, a cohort-based course provides that.

What subjects can you explore through free online courses?

Subject offerings span an unusually wide range for a “free” category. MIT OpenCourseWare covers physics, thermodynamics, and architecture, while CS50 and Stanford Code in Place focus on computer science. Other options include StanfordOnline’s Principles of Economics, HarvardX’s Justice for philosophy, and the CDC Museum’s Public Health Academy for students interested in epidemiology. Immerse Education’s Online Research Programme offers the broadest range, covering more than 20 subjects tailored to your specific interest.

How selective are free online courses for high school students?

Most free online courses have completely open enrollment with no application process, including MIT OpenCourseWare, CS50, and HarvardX’s Justice. A few exceptions exist: the CDC Museum’s Public Health Academy admits roughly 75 students, and Virtual NSLI-Y admits about 10 students per language class. Immerse Education’s Online Research Programme doesn’t publish a specific acceptance rate but involves an application process for its personalized mentorship format.

Is Immerse Education a good option for pursuing independent research for free?

Immerse Education’s Online Research Programme is a strong choice if you want individualized, Oxford-style mentorship rather than a pre-recorded lecture course. Offered in 1:1 or small group formats across more than 20 subjects, including AI, psychology, and economics, the program has you work with a tutor to write an academic research paper. You’ll receive written feedback, the chance to publish your research, and an invitation to present at the Immerse Online Symposium, all while remaining free with selected scholarship places available.

What Comes After Your Free Online Course?

Choosing among these free online courses for high school students gives you genuine access to university-level material without any financial barrier.

Once the course ends, you can turn that self-directed learning into a clearer sense of your academic and career direction.

The independence, subject knowledge, and study habits you built become a strong foundation for stronger university applications ahead.

Keep building on what you started this summer by exploring our University Preparation blogs for guidance on your next steps.