Background: The Sustainable Development Goals draw attention to the need for further improvements in reproductive health in low-resource settings. In Burkina Faso, the uptake of postpartum contraception, postnatal care attendance and the practice of exclusive breastfeeding are low. Men take many decisions that affect women and newborns’ health, despite having little exposure to health information. We hypothesised that a strategy to involve men in facility-based maternity care, in an urban area with high antenatal care attendance, would improve adherence to recommended healthy practices after birth. Methods: This was a mixed-methods study. Focus group discussions and consultations informed the development of an intervention with three components: A) a group discussion with male partners of pregnant women, B) a couple counselling session during pregnancy, and C) partner participation in the pre-discharge postpartum consultation. This was tested through a randomised controlled trial. 1144 pregnant women were enrolled in 5 primary health centres in Bobo-Dioulasso, and randomised 1:1 to intervention or control (routine care only). Participants were followed up at 3 and 8 months postpartum. For process evaluation, 40 semi-structured interviews were conducted with women, men and health workers. Results: Three quarters of male partners in the intervention arm attended at least 2 of 3 components. The intervention increased attendance at outpatient postnatal care (at least 2 consultations), exclusive breastfeeding at 3 months postpartum, effective modern contraception use at 8 months postpartum, especially long-acting methods, and improved an unvalidated measure of relationship adjustment. Several factors influencing adherence to the intervention emerged from the qualitative process data. The intervention appears to have worked mainly by increasing male knowledge on key topics and promoting couple communication and shared decision-making. Providers reported specific implementation challenges. Conclusion: Gender-transformative interventions to involve men as supportive partners in maternity care can improve adherence to recommended healthy practices among postpartum women.