In the West African nation of Niger, adolescent girls have the highest total fertility rate in the world, attributable to high rates of early marriage and childbirth. Gender norms that place men in decision-making positions and charge women with childbearing and childrearing, preclude engagement in discussions about fertility and family planning (FP) and as a result, contraceptive use remains low. As men are increasingly included in FP promotion efforts alongside women, it is important to understand the forces that shape couples’ interactions in the FP process. Utilizing data from married adolescent girls and their husbands in the Dosso region of Niger, this dissertation studies individual-, family-, and community-level factors to better understand how couples communicate about contraception and make decisions about actual contraceptive use. First, this work assesses the effects of couples’ individual attitudes about FP on spousal communication about contraception. This includes the separate, joint, and interacting effects of adolescent wives’ and husbands’ individual attitudes and their relationship with recent discussions about contraception, including those that were wife-initiated and wife-led. Second, is an examination of the effects of a community-based, gender-synchronized FP promotion program, including individual- and group-based approaches, on spousal communication about contraception. A study of the potential mediating effects of spousal communication about contraception sheds light on whether this is an important intermediate outcome of such programs. Finally, this dissertation seeks to characterize men’s social networks and their impact on men’s FP-related attitudes and behaviors. The work will also explore how FP messages spread through these networks to spur social change. Findings will help advance the study of relationship dynamics as they pertain to contraceptive use and improve the design and implementation of programs that aim to encourage more equitable FP decision-making.