The Math Circularis a free online magazine with educator resources such as articles, activities, and more! (You can also browse back issues of our previous magazine, the MTCircular.)
The Journal of Math Circles (JMC), published at Central Washington University, offers high-quality, practitioner-focused resources for outreach leaders through the dissemination of local knowledge to the broader mathematical community. Articles are authored by and for mathematics professionals, including K-12 teachers, who organize a wide range of community-responsive outreach programs across the globe.
The MSRI/AMS Mathematical Circles Library is a book series intended for leaders and participants in mathematical circles. Books typically include interesting and well-tested problems fostering a greater awareness and appreciation of mathematics and its connections to other disciplines and everyday life.