According to Self-Efficacy Theory (SET; Bandura, A. (1977). Self-efficacy: Toward a unifying theory of behavioral change. Psychological Review, 84(2), 191–215), social networks and support are important in developing beneficial levels of self-efficacy. However, empirical evidence of the relationship between social networks and self-efficacy is lacking, especially concerning exercise self-efficacy. Using SET and Social Network Analysis, this study examines factors related to six aspects of exercise self-efficacy among CrossFit participants, with a particular focus on social networks and support. Members from two CrossFit gyms (N=127; 35.55 ± 12.89 years, 66.9% female) completed surveys assessing various aspects of exercise self-efficacy by indicating their confidence in completing activities that require 1) effort, 2) resistance, 3) agility, 4) coordination, 5) balance, and 6) strength. Participants also reported their mastery of CrossFit exercises, social connections within CrossFit, sense of community, and emotions elicited through exercise. Linear network autocorrelation models revealed a person’s position within their social network (e.g., degree, closeness) and the self-efficacy scores of their social contacts were associated with participants’ effort self-efficacy (Gym 1: R2=0.26, p<.001; Gym 2: R2=0.82, p<.001), agility self-efficacy (Gym 1: R2=0.43, p<.001; Gym 2: R2=0.63, p<.001), and strength self-efficacy (Gym 1: R2=0.45, p<.001; Gym 2: R2=0.84, p<.001). This study supports the SET and a growing body of literature documenting the relationship between social networks and self-efficacy and suggests social network indices and effects are important in explaining aspects of exercise self-efficacy in these CrossFit networks.