BackgroundFever is one of the common clinical symptoms found among children suffering from various illnesses. India carries a substantial burden of febrile illness among under-five children which heighten the risk of malnutrition, mortality and morbidity. This study aims to determine the factors associated with delay in treatment-seeking for fever among under-five children in India.MethodsA cross-sectional study was carried out using the large-scale nationally representative data from the National Family Health Survey (NFHS-4), conducted in 2015–2016. The data were collected by using four survey questionnaires i.e., Household Questionnaire, Woman’s Questionnaire, Man’s Questionnaire, and Biomarker Questionnaire. Delay in treatment-seeking was defined as taking a child for treatment after 24 hours of fever onset. Bivariate and multivariate logistic regression models were performed to assess the factors associated with delay in treatment-seeking behaviour for fever in under-five children.ResultsIn India, 31.12% (n = 7229) of the caregivers sought treatment for children after 24 hours of the onset of fever. Findings show no significant differences in delay in treatment-seeking behaviour by age groups and sex of children. Multivariate analysis revealed that the odds of delay in treatment-seeking behaviour of fever were higher among children from the poorest wealth quintile (AOR: 2.06; 95% CI: 1.85, 2.31), belonging to the scheduled tribe (AOR: 1.35; 95% CI: 1.24, 1.48), children who resided in rural areas (AOR: 1.14; 95% CI: 1.07, 1.22), children from the northeast region (AOR: 1.29; 95% CI: 1.14, 1.46), and children of caregivers who perceived distance to health facilities as a ‘big problem’ (AOR: 1.16; 95% CI: 1.09, 1.23).ConclusionThe study shows a high prevalence of delay in seeking treatment for fever among caregivers of under-five children in India. Delay in seeking treatment is associated with socio-demographic and socio-economic factors. Therefore, there is a need for intensified health promotion programs to sensitize caregivers on the importance of early health-seeking behaviour.