BACKGROUND: To reduce the prevalence of anemia, the Indian government recommends daily iron and folic acid supplements (iron supplements) for pregnant women and weekly iron supplements for adolescents and all women of reproductive age. The government has distributed free iron supplements to adolescents and pregnant women for over four decades. However, initial uptake and adherence remain inadequate and non-pregnant women of reproductive age are largely ignored. The aim of this study is to examine the multilevel barriers to iron supplement use and to subsequently identify promising areas to intervene. METHODS: We conducted a qualitative study in the state of Odisha, India. Data collection included key informant interviews, focus group discussions with women, husbands, and mothers-in-law, and direct observations in health centers, pharmacies and village health and nutrition days. RESULTS: We found that at the individual level, participants knew that iron supplements prevent anemia but underestimated anemia prevalence and risk in their community. Participants also believed that taking too many iron supplements during pregnancy would "make your baby big" causing a painful birth and a costly cesarean section. At the interpersonal level, mothers-in-law were not supportive of their daughters-in-law taking regular iron supplements during pregnancy but husbands were more supportive. At the community level, participants reported that only pregnant women and adolescents are taking iron supplements, ignoring non-pregnant women altogether. Unequal gender norms are also an upstream barrier for non-pregnant women to prioritize their health to obtain iron supplements. At the policy level, frontline health workers distribute iron supplements to pregnant women only and do not follow up on adherence. CONCLUSIONS: Interventions should address multiple barriers to iron supplement use along the socio-ecological model. They should also be tailored to a woman's reproductive life course stage: adolescents, pregnancy, and non-pregnant women of reproductive age because social norms and available services differ between the subpopulations.