Mozilla Learning Network — Lessons and platforms from Mozilla on everything from basic and advanced digital literacy, privacy, programming, and more — also has some incredible online and offline teaching activities.
TED — Informational videos on a variety of topics from around the world.
TED-Ed — Curated educational videos.
CK-12 Foundation — Textbooks, flashcards, simulations, and examples across all secondary school subjects.
Curriki — Curates content in a variety of disciplines, highlighting noteworthy teachers and content.
Hopelink — A collection of lesson ideas in adult education, reading, writing, math and financial literacy, the GED, and workplace skills, etc. Special lesson ideas for working with ESL and learning-disabled students.
Exploring the Environment — Problem-based learning approach to studying climate change and weather. Students will use data from NASA and various climate science data sets to study different aspects of global warming.
LearningMedia — A free service that brings together digital content from trusted organizations and public broadcasters, including videos, games, audio clips, photos, and lesson plans.
Museum of Science + Industry Chicago — Series of games, apps, videos, and activities that teach science in an interactive, easily accessible way.
National Geographic Kids — Many resources on different kinds of animals and their environments.
OER Commons — Vast database of teacher-created curriculum. The content is vetted for credibility and provides citations for reference.
Open Culture — Free cultural and educational media, including audio books, online courses, certificate courses/MOOCs, movies, eBooks, K-12 resources, and language lessons.
Power Up — Information about how electricity works, where it comes from, and, most importantly, how to stay safe. There are fun, interactive games where kids can build their own circuits, trace how electricity travels to homes, and take quizzes to test their knowledge.
ReadWriteThink — Links to subject-specific curriculum sites.
SmartHistory — A great art history resource. This site features content organized by time period, style, artist and theme. It's more of a gallery of art history than a textbook.
WatchKnowLearn — A wiki that allows teachers to edit/remix lessons by finding videos to use in lessons and allows educators to connect with other educators.
Weather Wiz Kids — Explore the fascinating world of weather. It has explanations of many different weather phenomena, and a large variety of games, jokes, and quizzes about weather.
Animated Explanations — Animated explanations, interactive tutorials and instructional videos.
No Excuse List — List of lists for all sorts of education resources online – academics, art, cooking, DIY, etc.
Project Euler — Challenging mathematical/computer programming problems.
Maker Education Initiative — Non-profit organization that provides educators and institutions with the training, resources, and community of support they need to create engaging, inclusive, and motivating learning experiences through maker education.
Maker Share — A community of makers sharing what they can do.
Intel Education Teaching Tools and Resources — Activities and lessons, many of which are creative and makerspace-related.
Curiosity Machine — Science education non-profit offers flexible STEM education tool that can be adapted to any learning environment.
Iridescent — Education non-profit that trains professional engineers, scientists, and parents to deliver cutting-edge STEM education to underserved girls, children and their families through two flagship programs: Technovation and Curiosity Machine.
NASA — US space agency – has a wealth of resources in education, particularly in STEM.
Smithsonian Education — Over 2,000 resources for educators and teachers to use.
ABCya — A wide variety of activities, lessons, and games for students to learn about many different concepts in math and language arts.
APlusMath — Provides interactive math activities to help students improve their math skills.
BBC BiteSize Science — Learning and revision resources, learner guides for primary and secondary students, and class clips (videos for teachers to use in the classroom).
Smithsonian Curriculum & Resources — Videos, games, resources, ebooks, curriculum, and apps. Be sure to check the "free resources only" filter.
DIY.org — Online community for kids to focused on building skills and STEM-related activities.
Good Thinking — Animated series that helps teachers teach science.
HowToSmile — Over 3,500 science and math activities — search and filter by age, material costs, and learning time.
IBM Activity Kits — Kits aimed at helping not-for-profit organizations understand their technology needs, sharing the fun of math and science with school children.
IXL — List of key math skills that students should learn in different grades. For each concept, they provide practice questions that become harder as you correctly answer them.
Kidport — Many offers lots of "think-and-learn" math activities for grades K-8
PBS Kids — Many engineering games that allow students to solve mysteries with Curious George, build robots, and create their own engineering challenges to solve.
Science Kids — Contains many different resources for students to learn about the various concepts of engineering. There are fun project ideas, quizzes, experiments, and videos to engage kids.
Sheppard Software — Hundreds of free, online, educational games for kids.
Smithsonian Learning Lab — Digital resources from across the Smithsonian's 19 museums, 9 major research centers, the National Zoo, and more, can be used together, for learning.
Teaching Engineering — Searchable, web-based digital library collection populated with standards-based engineering curricula for use by K-12 teachers and engineering faculty to make applied science and math come alive through engineering design in K-12 settings.
Web Adventures — Six interactive adventures in science where you will help solve a problem.