Our understanding of community college pathways to baccalaureate degrees in science, technology, engineering, and math (STEM) is remarkably incomplete, despite growing recognition of the sizeable role that community colleges stand to play in increasing the number of students who enter STEM baccalaureate programs, particularly underrepresented students. Here, we drew from data on nearly 3 million students to analyze participation in and navigation of the STEM transfer curriculum in community colleges, while focusing primarily on the fields of math, chemistry, and physics. We found that a large number of students enrolled in college-level STEM coursework, and many of these students were of demographic groups that are underrepresented in STEM fields. Yet, comparatively few students progressed into advanced STEM coursework. Moreover, the contribution of community colleges to resolving longstanding demographic inequities in STEM is constrained by pronounced gender and racial/ethnic differences in points of entry into the STEM curriculum, pathways through STEM, and manner of exit from STEM. As a result, much of the considerable potential of community colleges to improve STEM baccalaureate production and equity of opportunity in STEM remains largely unrealized at this point. We conclude with practical recommendations and a detailed research agenda to guide future inquiry on this subject.