The extent to which young women with substance use disorders (SUDs) affiliate with Alcoholics Anonymous (AA) or other 12-Step groups is currently unclear. This administrative data analysis examined 12-Step involvement and its impact on outcome during the first 6 months following treatment among a sample of young adults attending 12-step-based residential treatment. Young women were just as likely as similar-aged young men to attend 12-Step meetings and engage in prescribed 12-Step practices like getting a sponsor. Frequency of meeting attendance predicted abstinence status and number of drinking days at 6 months in women, whereas 12-Step experiences (e.g., getting a sponsor, considering oneself an AA member) predicted drinking days in men. The results contribute to knowledge of SUDs and their treatment among women in their late teens and early twenties, a population that has been quite understudied in the literature. (Published Abstract)