Girls' time in sex-typed leisure activities was studied across 2 years in middle childhood (n = 98, M = 8.2 years in Year 1), early adolescence (n = 106, M = 11.7 years), and middle adolescence (n = 86, M = 14.9 years). In annual home interviews, White middle-class girls, mothers, and fathers rated their gendered attitudes, interests, and personality qualities, and saliva samples were used to assess testosterone; activity data were collected in 7 nightly phone interviews. Girls spent more time in feminine than masculine activities except in early adolescence. Girls' and parents' personalities and interests predicted sex-typed activities at each developmental period, but associations between testosterone and activities emerged only in middle childhood.