Pre-exposure prophylaxis (PrEP) is effective for preventing HIV among HIV-serodiscordant heterosexual couples. Gender roles may influence perceived personal and social risks related to HIV-prevention behaviors and may affect use of PrEP. In this study, interviews and focus groups were conducted with 68 individuals from 34 mutually disclosed serodiscordant heterosexual partnerships in Thika, Kenya. Sociocultural factors that affect adherence to PrEP were explored using grounded analysis. Three factors were identified, which shape perceptions of PrEP: gendered power dynamics and control over decision-making in the household; conflicts between risk-reduction strategies and male sexual desire; culture-bound definitions of women's work. Adherence to PrEP in the Partners PrEP Study was high; however, participants articulated conflicting interests related to PrEP in connection with traditional gender roles. The successful delivery of PrEP will require understanding of key social factors, particularly related to gender and dyadic dynamics around HIV serostatus.