Limited knowledge exists on sustained adherence to small-quantity lipid-based nutrient supplements for pregnant and lactating women (LNS-PL) and how this compares with that of other prenatal supplements. To address these gaps, a random subsample of women (n = 360) during pregnancy, early (6- to 12-week post-partum) and late (12- to 24-week post-partum) lactation, from an ongoing effectiveness trial in Bangladesh, was selected for in-home interviews about LNS-PL or iron/folic acid (IFA) use and preferences. Prevalence of high adherence (≥70% of the recommendation) based on self-reported supplement consumption was 67%, 68% and 81% among LNS-PL recipients during pregnancy, early and late lactation, and was 87% and 71% among IFA recipients during pregnancy and early lactation, respectively (P = 0.044). Programmatic factors (e.g. distribution and visits by programme staff) were consistently statistically significantly associated with reported high adherence. Among LNS-PL recipients, high overall supplement acceptability score [odds ratio (OR): 8.62; 95% confidence interval (CI) 3.53, 20.83] and use of reminder techniques (OR: 4.41; 95%CI 1.65, 11.76) were positively associated, and reported vomiting at enrollment was negatively associated (OR: 0.34; 95%CI 0.14, 0.80), with reported high adherence. Selected women (n = 16) and key informants (n = 18) participated in in-depth interviews about perceptions and acceptability of LNS-PL. Women perceived benefits of taking LNS-PL, but some faced barriers to consumption including aversion to odour and taste during pregnancy, forgetfulness and disruptions in supply. To achieve high adherence, results from this study suggest that maternal supplementation programmes should focus on programmatic barriers and consider incorporating reminder techniques. Organoleptic acceptability of LNS-PL, particularly during pregnancy, may also need to be addressed.