Open Educational Resources (OER)

OER means free + openly-licensed teaching material that anyone can copy, remix, and redistribute. The 2024-26 catalogue is enormous and high-quality. Pair with a LMS, course authoring, and content discovery.

The famous free curricula

• ★ ★ MIT OpenCourseWare (OCW) — free; CC-BY-NC-SA; 2,500+ MIT courses with full lecture notes, problem sets, exams. OCW Scholar versions include video lectures.
• ★ ★ Khan Academy — free; CC-BY-NC-SA; K-12 + early-college math, science, humanities; pre-K Khan Academy Kids is also free. 2024+: Khanmigo AI tutor (paid, see AI tutors).
• Open Yale Courses — free; lecture videos for ~40 Yale courses.
• Stanford Online / Stanford Engineering Everywhere — free; older course archive.
• edX free audit — free; pay only for verified certificate. Most edX courses are auditable for free.
• Coursera free audit — free for most non-degree courses.
• FutureLearn — paid + free; UK / Open University-anchored.

OER textbooks

• ★ ★ OpenStax (Rice University) — free; CC-BY; ~70 peer-reviewed open textbooks for K-12 and introductory college. Used by 2.4M+ students. The single biggest open-textbook win.
• ★ LibreTexts — CC-BY-NC-SA; modular open-textbook library across STEM, humanities, social science. Hosted on a custom MindTouch fork.
• BCcampus OpenEd — Canadian provincial OER hub.
• OpenStax CNX (Connexions) — predecessor; deprecated 2022, content folded into LibreTexts.
• Saylor Academy — free; CC-BY courses with optional certificates.

Subject-specific OER hubs

• OER Commons (ISKME) — free; the largest cross-subject OER catalogue.
• MERLOT — free; CSU-led; multimedia + simulations.
• MoodleNet — federated OER for Moodle teachers.
• Wikibooks / Wikiversity / Wikisource — free; CC-BY-SA; community-built.
• Project Gutenberg — free; ~70k public-domain ebooks.
• Internet Archive / Open Library — free; massive scanned-book + media archive. Controversial National Emergency Library / Hachette ruling — flag the legal gray for digital lending in classrooms.
• Standard Ebooks — free; CC0; beautifully-typeset public-domain ebooks.

K-12 specific

• CK-12 Foundation — free; CC-BY-NC; FlexBook textbooks aligned to US standards; sims; adaptive practice. See science simulations.
• Curriki — free; K-12 OER community.
• EngageNY / NYSED — free; New York State curriculum.
• EL Education K-8 ELA / EL Math — free; high-quality literacy curriculum.
• Illustrative Mathematics — free + paid; OER math curriculum (6-12).
• OpenSciEd — free; CC-BY; NGSS-aligned middle-school science.

Specific subjects (free)

• 3Blue1Brown / Grant Sanderson — free YouTube; canonical math intuition (linear algebra, calculus, neural nets).
• Crash Course (PBS) — free YouTube; world history, biology, chemistry, etc.
• Veritasium, Numberphile, Computerphile, MinutePhysics, SmarterEveryDay, Kurzgesagt — free YouTube science / math channels.
• MIT BLOSSOMS — free; high school STEM video + activity library.

Open licences (know which you're using)

• CC0 — public domain dedication.
• CC-BY — attribute, do anything.
• CC-BY-SA — attribute, share-alike (Wikipedia).
• CC-BY-NC — non-commercial only — ⚠ not technically "open" by the SPARC / Hewlett definition; blocks reuse in for-profit textbooks.
• CC-BY-NC-SA — most restrictive of the OER-grade licences.
• CC-BY-ND — no derivatives — ⚠ not OER under common definitions.

Pick this if…

• University-level lecture material: MIT OCW or Open Yale.
• K-12 default free: Khan Academy + OpenStax.
• Open textbook for college class: OpenStax.
• Modular open textbook STEM: LibreTexts.
• OER-aligned NGSS science: OpenSciEd.
• Public-domain ebooks: Project Gutenberg or Standard Ebooks.
• Free MOOC audit: Coursera or edX (audit track).