Student success in science, technology, engineering, and math (STEM) is a major concern in higher education. While overall 6-year graduation rates are around 60% nationally (National Center for Education Statistics, 2016), only about 40% of students who enter college intending to major in a STEM field complete a STEM degree within 6 years. Studies have identified some of the issues affecting retention in STEM. There has been increased attention on the first two years of college, as many of these issues impact students as they transition to college, and negative experiences are worst in introductory courses. A growing body of research suggests that the problems faced by STEM students are much more multifaceted than currently understood, particularly when trying to serve low-income, first-generation, and underrepresented minority students. Increasingly, there are recommendations for multifaceted interventions that combine several reforms or supports. This article describes a key lesson from the California State University (CSU) STEM Collaboratives project: knowledge that can help underrepresented students in STEM succeed is typically kept in separate organizational silos, and the key to supporting these students is creating a unified community of support that builds bridges between these silos. The authors illustrate how campuses that are able to bridge these silos were able to improve the success of students in STEM in terms of retention, GPA, and psychosocial outcomes, such as sense of belonging and academic self-efficacy.