This study examined the influence of ego networks on first-year teachers (1YTs) regarding belief persistence, formation, and change. The study employed a mixed methodology of interviews, survey questionnaires, and an ego-centric social network analysis of 1YTs. Findings suggest that 1YTs' beliefs can be influenced by ego networks, with some individuals showing greater influence than others in a network. The ego networks of 1YTs showed varying degrees of stability over the first year, with many networks undergoing structural changes during the first few months of 1YTs' careers. Implications for this research include structuring formal teacher induction programs that encourage interactions between diverse individuals and 1YTs, monitoring structural changes of ego networks during early-career years, and empowering administrators to increase their visibility and interactions with 1YTs.