This is a comparative study of work-family conflict in the private and public sector of Nigeria. It comparatively analyzed the impact of long hours working mothers spend at work on child care obligation. The study adopted a survey and descriptive research design. The target population consisted of 524 married women selected from United Bank for Africa (UBA), Nigerian Brewery, Ministry of Commerce and Industry and Ministry of Labour and productivity representing the private and public sectors. A hypothesis was formulated to guide the study. Open-ended and close- ended questionnaire and interview were used for data collection. The Cronbach Alpha test was used to test for the internal consistency, and the reliability index of the instrument. The data gather was analyzed using chi-square and independent t test. The findings revealed that the independent sample t-test analysis of the differences between the hours women spend at work and the marital obligation of childcare based of both sectors showed that women working in the private sector (M = 2.54, SD = 0.64) spend significantly more time at work than those in the public sector [M = 1.87, SD = 0.48; t(522) = 13.32, p < 0.05]. Also, the result shows that women working in the private sector (M = 23.06, SD = 10.96) scored significantly higher in variation in terms of time spent at work as well as scoring lower in child care obligation than their counterparts working in the public sector [M = 27.98, SD = 8.08; t(522) = -5.74, p < 0.05. The study recommended that government should prosecute private sector organizations that fail to inculcate and implement family flexibilities that will enable married women to cushion the effect of work-home conflict. Family flexibility that allows married women spend less time at work place or to work from home should be encouraged in the private sector, and maternity leave allowance for nursing mothers should be extended to 5-6 months from the usual three months.