Background India is the only nation where young girls have greater risks of under-5 mortality than boys. We test whether female disadvantage in breastfeeding and food allocation can account for India’s gender disparities in under-five mortality rates.

Methods We analysed round 3 of India’s National Family and Health Survey 2005–2006, with focus on first- and second-born children aged 0–59 months (number of siblings = 20,395) in 29 Indian states. Multivariate regression and Cox proportional hazards survival analysis of gender biases were performed, with statistical models disaggregated by birth order and sibling gender, as well as adjusted for maternal age and education, maternal fixed effects, urban residence, household deprivation, and other potential socio-demographic confounders. Our main outcome measures included mothers’ reported practices of WHO/UNICEF recommendations for breastfeeding initiation, exclusivity, and total duration, as well as children’s consumption of 24 individual food items (ages 6–59 months), and child survival (ages 0–59 months).

Results Young girls were breastfed on average for 0.45 months less than boys (95% CI: = 0.15 months to 0.75 months, p = 0.004). However, there was no gender difference in the likelihood of breastfeeding initiation (OR = 1.04, 95% CI: 0.97 to 1.12) or exclusive breastfeeding (OR = 1.06, 95% CI: 0.99 to 1.14). The differential risks of breastfeeding cessation emerged between ages 12 and 36 months in second-born females. Compared with boys, Indian girls also had lower reported consumption of fresh milk by 14% (95% CI: 79% to 94%, p = 0.001) and breast milk by 21% (95% CI: 70% to 90%, p < 0.000). Survival analyses of mortality showed that each additional month of breastfeeding duration was associated with a 24% lower risk of mortality (OR=0.76, 95% CI: 0.73 to 0.79, p < 0.000). Taken together, girls’ shorter breastfeeding duration accounted for about an 11% increased probability of dying before age 5, accounting for about one-half of their survival disadvantage compared with other low-income countries.

Conclusion Young Indian girls are breastfed for shorter periods than boys and consume less fresh milk. Future research is needed to investigate the role of alternative factors driving India’s female survival disadvantage, such as inequitable healthcare access.