Despite the positive effects of sports participation on young girls' development and well-being, gender disparities persist, and sport participation drops dramatically as young girls grow into adolescence. Current reports (e.g. Tucker Center, 2018) confirm persistent gender stereotypes that influence participation, especially in masculine-typed sports (MTS). Socializing agents (e.g. parents, siblings, peers) play a key role in shaping the social climate that influences young girls' sports participation, and that influence is manifested through social support functions. The purpose of this study was to examine the role of socializing agents on dropout and continuing participation of adolescent girls in MTS. A total of 118 US women and a smaller sample of Israeli women (n = 28) completed a survey on social support they received during their adolescent sport experiences. Findings revealed that social support was greater for girls who engaged in MTS than girls who engaged in neutral and feminine sports; social support was greater for girls who continued participation than for those who dropped out; and social support was greater for US girls than for Israeli girls.