Use of family planning (FP) saves the lives of mothers and children, and contributes to better economic outcomes for households and empowerment for women. In Tanzania, the overall unmet need for FP is high. This study aimed: (1) to use focus group data to construct a theoretical framework to understand the multidimensional factors impacting the decision to use FP in rural Tanzania; (2) to design and pilot-test an educational seminar, informed by this framework, to promote uptake of FP; and (3) to assess acceptability and further refine the educational seminar based on focus group data collected 3 months after the education was provided.We performed a thematic analysis of 10 focus group discussions about social and religious aspects of FP from predominantly Protestant church attenders prior to any intervention, and afterwards from six groups of church leaders who had attended the educational seminar.Key interpersonal influences included lack of support from husband/partner, family members, neighbours and church communities. Major intrapersonal factors impeding FP use were lack of medical knowledge and information, misconceptions, and perceived incompatibility of FP and Christian faith. Post-seminar, leaders reported renewed intrapersonal perspectives on FP and reported teaching these perspectives to community members.Addressing intrapersonal barriers to FP use for leaders led them to subsequently address both intrapersonal and interpersonal barriers in their church communities. This occurred primarily by increasing knowledge and support for FP in men, family members, neighbours and church communities.