This guide to forming a Community of Practice (CoP) to increase quality/quantity of STEM learning is based on lessons learned by a network of five CoPs across California – the Power of Discovery STEM2. The guide’s author distinguishes CoPs from “other more traditional professional development settings in that they are not focused on content delivery but rather are designed as a “by us, for us” collective learning space.” The CoPs profiled are all peer networks with relevant STEM learning opportunities engaging in collaborative event planning for diverse stakeholder groups. The guide details the formation and implementation of a CoP.