This mixed-methods study aimed to determine the level of male involvement in the prevention of mother-to-child transmission (PMTCT) services in Haiti and identify barriers and associated factors. From May to June 2018, a questionnaire was used to measure the level of male involvement. Semistructured interviews with pregnant women were also conducted. Multivariate linear regression and qualitative content analyses were performed to explore factors associated and barriers to male partners' involvement in PMTCT services. One hundred and two pregnant women living with HIV completed the questionnaire. About 47% of male partners had a high level of involvement. Specifically, 90% financially supported their spouse, and 82% knew her appointment date at the antenatal clinic (ANC). Only 25% of male partners accompanied their spouse to the ANC, and 19% routinely used a condom during sexual intercourse. Factors associated with male involvement in PMTCT were being married and sharing HIV status with the male partner. Male partners with a positive HIV status were more likely to be involved in PMTCT. Qualitative findings revealed that barriers to male involvement included the conflict between opening hours of the ANC and the male partner's schedule, waiting time at the ANC, and the perception of antenatal care as being women's business. Overall male partners' involvement in PMTCT services is moderate. Gender relations, sociocultural beliefs, and care organization are likely to hinder this involvement. Developing and implementing contextually and culturally accepted strategies for male partners of pregnant women could contribute to strengthening their involvement in the PMTCT program.