AbstractBalanced energy protein (BEP) supplementation is an efficacious intervention in pregnancy for improving birthweight and is recommended by World Health Organization (WHO) in countries with high maternal undernutrition. Few countries have implemented BEP programmes due in part to high cost, lack of data on acceptability and feasibility, and complexity of delivery. We sought to address implementation gaps in BEP interventions through a formative study designed to understand implementation outcomes. We conducted 52 in‐depth interviews and 8 focus‐group discussions with married women of reproductive age, family members, health care providers and pharmacists in three unions of the Gaibandha district in rural Bangladesh. Interviews were translated and transcribed in English and analysed using an analytic framework for implementation science in nutrition. BEP was viewed as an acceptable and appropriate intervention to combat undernutrition in this setting. There was a lack of clarity on who should or could be responsible for providing/distributing BEP in a way convenient to mothers. Many participants preferred door‐to‐door delivery and thought this approach could address social and gender inequities, but providers mentioned already being overworked and worried about adding new tasks. Participants were concerned about the affordability of BEP and opportunity costs associated with travel to proposed distribution sites such as ANC or pharmacies. Women in these communities do not always have the agency to travel without supervision or make purchasing decisions. BEP supplementation is a complex intervention; future trials seek to assess ways to overcome these implementation challenges and inform a long‐term systems‐owned BEP intervention.