Despite progress in maternal and child health, significant gap and high inequity persist in unmet health needs, creating a barrier to universal health coverage. Previous studies have analysed inequity of health outcomes and healthcare availability, but limited research is available on delayed or not‐seeking treatment. Research conducted on unmet treatment lacks emphasis on vulnerable groups; women and children. The objective is to fill this research gap by estimating the contribution of socio‐economic factors to inequality in the unmet health needs of women and children. This study uses the concentration index, concentration curve and horizontal inequity index to estimate inequality. A decomposition analysis is conducted to estimate the contribution of each socio‐economic factor to inequality. The need‐adjusted index shows the inequity due to non‐need factors. The unmet health needs are significantly higher among socioeconomically disadvantaged groups. In addition to wealth, factors such as caste (4.43% and 7.23%), education (7.27% and 13.05%), media exposure (3.88% and 6.39%) and distance problem (5.35% and 14.61%) contribute to the inequity for both women and children. A negative horizontal inequity index confirms that non‐need factors are major contributors to inequity. Findings add new theoretical insights on healthcare accessibility and inform policymakers on factors creating disadvantages in treatment‐seeking. Action plans for universal health coverage need to incorporate social and institutional factors in policy and budgetary allocations. Further, health‐card system, health‐record‐keeping practices and community‐health officer/clinic can improve treatment seeking.