Purpose: This study investigates the reasons teachers seek instructional assistance from their colleagues. By examining both the reasons why teachers seek assistance and considering which reasons for seeking assistance predict shifts in teaching practice, this analysis provides new insights into how schools can leverage teachers' social networks for organizational change. Design/methodology/approach: Drawing on interview and survey data from a sample of 52 schools across seven districts in the United States, we first qualitatively explore the reasons teachers seek instructional assistance, based on patterns in teachers' self-reported descriptions of their instructional advice-seeking. Then, we apply hierarchical linear models to predict which individual characteristics and organizational features influence the reasons' teachers seek assistance and which reasons for seeking assistance influence their subsequent shifts in teaching practice. Findings: Teachers' positions in their social networks, their experience levels and their organizational contexts predict the reasons for which they seek instructional assistance. In addition, teachers seeking advice based on perceptions of their peers' experience or resource access predicts positive shifts in teaching practice; however, fewer than half of teachers' instructional-advice seeking ties reported in our sample were motivated by either of these two reasons. Practical implications: The findings highlight the potential for school leaders and policymakers to improve teaching practice by making educators' experience and resources more accessible within schools and creating structures that enable collaboration. Originality/value: This paper addresses a gap in social network literature by moving beyond a structuralist analysis of teachers' collegial networks to investigate teachers' motivations for pursuing advice-seeking ties. [For the corresponding grantee submission, see ED616527.]