OBJECTIVE: To model the potential impact and equity impact of fortifying rice on nutritional adequacy of different subpopulations in Nepal. DESIGN: Using 24-h dietary recall data and a household consumption survey, we estimated: rice intakes; probability of adequacy (PA) of eight micronutrients commonly fortified in rice (vitamin A, niacin (B3), pyridoxine (B6), cobalamin (B12), thiamin (B1), folate (B9), Fe and Zn) plus riboflavin (B2), vitamin C and Ca and mean probability of adequacy (MPA) of these micronutrients. We modelled: no fortification; fortification of purchased rice, averaged across all households and in rice-buying households only. We compared adequacy increases between population subgroups. SETTING: (i) Dhanusha and Mahottari districts of Nepal (24-h recall) and (ii) all agro-ecological zones of Nepal (consumption data). PARTICIPANTS: (i) Pregnant women (n 128), mothers-in-law and male household heads; (ii) households (n 4360). RESULTS: Unfortified diets were especially inadequate in vitamins B12, A, B9, Zn and Fe. Fortification of purchased rice in rice-purchasing households increased PA > 0·9 for thiamin, niacin, B6, folate and Zn, but B12 and Fe remained inadequate even after fortification (PA range 0·3-0·9). Pregnant women's increases exceeded men's for thiamin, niacin, B6, folate and MPA; men had larger gains in vitamin A, B12 and Zn. Adequacy improved more in the hills (coefficient 0·08 (95 % CI 0·05, 0·10)) and mountains (coefficient 0·07 (95 % CI 0·01, 0·14)) but less in rural areas (coefficient -0·05 (95 % CI -0·09, -0·01)). CONCLUSIONS: Consumption of purchased fortified rice improves adequacy and gender equity of nutrient intake, especially in non-rice-growing areas.