Undernutrition remains a key public health burden in Nepal. This study aimed to measure knowledge, attitudes, and beliefs about nutritious food amongst mothers of 3 – 5-year-olds from rural and urban areas. A cross-sectional mixed-methods approach comprised a quantitative survey and qualitative focus groups. The community-based survey included 524 mothers of children who are no longer breastfed. Open-ended and structured questions investigated knowledge, beliefs and attitudes about nutritious food, child feeding patterns, and major barriers, food insecurity, and health-seeking behaviours. Focus groups were held with key informants, a thematic analysis was applied to the qualitative data. Results: Major barriers to recommending nutritious foods included: lack of knowledge (19%); cost (21%); and culture/beliefs (7%). Nearly 55% children were given fruit once a week. Almost 37% of mothers never gave meat, fish and egg regularly to their children and 34% did not choose healthy food from stores, and 12% lacked food. Most children (57%) had been taken at least once to a spiritual healer and 16% had been taken more than once. The qualitative analysis suggested that important factors of knowledge, attitudes, and beliefs about healthy diet are poverty, education, strong cultural beliefs, family size, household income, time and a growing preference for fast food. Conclusion: Knowledge of and attitudes towards nutritious food is still poor. Beliefs about food practice are strongly embedded in Nepal. Thus, this study shows that policymakers should consider a public health intervention and approach based around changing these largely cultural beliefs and behaviours.