This study examines the association between high school teachers' collegial networks and their own familiarity with, and practices related to, supporting students' admission to college. Using survey data collected at two time points from 163 teachers in four mid-Michigan high schools in 2011-2012, this study (a) employs cluster analysis to map collegial networks by school, and (b) uses social network influence modeling to examine how teachers may be influenced by their closest colleagues. Results of the cluster analysis find that all four high schools surveyed show evidence of distinct clustering by subgroups. Results from influence modeling show that while positive in almost all cases, the impact of teachers' exposure to colleagues is not significantly associated with a change in familiarity or practices related to college-going. However, interaction with program staff from a college-advising program is found to be related to a small positive change in some teacher practices.