<p>US colleges and universities are increasingly recognizing and supporting first-generation students—those whose parents have not earned a bachelor’s degree and who are therefore the first in their families to attend college. To investigate the extent to which first-generation student support has expanded and what factors have facilitated the expansion, I draw on original data collected from a nationally representative sample of 234 US higher education institutions. I find that 35.9% of universities have first-generation student supportive features, defined as dedicated offices or programs specifically designed to support first-generation students. Event history analysis reveals that universities that are more selective, committed to diversity, and connected to professional networks are more likely to adopt first-generation student supportive features. Furthermore, as more universities adopt these features, the diffusion of such practices accelerates. Overall, my findings suggest that not only universities’ internal characteristics but also the external environments in which they operate contribute to their growing commitment to first-generation student support.</p>