Middle class mothers (n = 169) of middle adolescents (M = 15.69 years old) in the U.S. rated how much they want to know and responded qualitatively about what they “always” and “never” want to know about adolescents' risky prudential (e.g., drinking alcohol, using illegal drugs), personal (e.g., teens' private conversations), and multifaceted (involving overlapping prudential and personal concerns) activities. Latent growth curve modeling over one year showed that mothers wanted to know most about prudential, less about multifaceted, and least about personal activities; wanting to know declined over time for each type of activity, but less for prudential than for other activities. With teen problem behavior controlled, psychologically controlling parenting, supportive and negative interactions with teens, knowledge of adolescents' activities, and teens' age were associated with individual differences in mothers' initial ratings and trajectories of wanting to know, although results varied by domain and were moderated by teen gender.