The Families Matter! Program (FMP) is a curriculum-based intervention designed to give parents and other primary caregivers the knowledge, skills, comfort, and confidence to deliver messages to their 9-12-year-old children about sexuality and practice positive parenting skills. A pre- and post-intervention evaluation study on FMP outcomes was conducted with 658 parent participants and their preadolescent children in two administrative wards in Tanzania in 2014. There was an increase in the proportion of study participants (parent-preadolescent pairs) that had positive attitudes toward sex education. On parent-child communication, the majority of participants (59-87%) reported having had more sexuality discussions. On communication responsiveness about sexual issues, scores improved in the period between surveys, with parents showing more improvements than preadolescents. Our results corroborate evidence from previous FMP evaluations, lending support to the conclusion that FMP is successful in promoting attitude and behavior change among parents and preadolescents in different cultural contexts.