Free music theory website by Robert Hutchinson
Music for the 21st Century Classroom is a free music theory site that covers most of the topics you’d learn in a college-level core music theory class. The units are arranged the same way you’d see in a textbook, but the musical examples aren’t limited to common practice period (classical) era music.

Hutchinson includes examples from pop, film scores, and more to make sure that everyone can connect to the music theory concepts presented in every lesson.