Interpersonal feedback from coaches may be instrumental in the formation of children's self-efficacy to learn or perform sport skills. We report on two studies that explored perceived sources of self-efficacy and relation-inferred self-efficacy (RISE) in one-on-one interviews with sport camp participants (N = 61; ages 7-12) and focus groups with recreational league participants (N = 28; ages 8-12). Participants' responses indicated that prior experiences and socially constructed interactions contributed to the development of self-efficacy and RISE beliefs. Results support Bandura's (1997) theorizing that self-efficacy is developed through processing of experiential feedback as well as Lent and Lopez's (2002) tripartite theory proposing interpersonal feedback from influential others contributes to children's RISE and self-efficacy.