A range of demographic and socioeconomic factors are known to account for enormous disparities in the uptake of maternal health care in low- and middle-income countries. In contrast, contextual factors such as child marriage are far less explored as a deterrent to the uptake of maternal health care. The present study aimed to assess the total effect of child marriage on the utilization of maternal health services in Nepal. This study drew on data from the Nepal Demographic and Health Survey 2016. The study restricted its analysis to a subsample of 3,970 currently married women of reproductive age who had at least one live birth in the five years preceding the survey. After descriptive analysis, logistic regression models were constructed to estimate adjusted odds ratios. The results of logistic regression controlling for confounders suggested child marriage decreased the likelihood of antenatal care visits (AOR 0.74; 95% CI 0.63–0.86), skilled attendance at delivery (AOR 0.66; 95% CI 0.56–0.78), facility-based delivery (AOR 0.65; 95% CI 0.56–0.77), and postnatal care use (AOR 0.80; 95% CI 0.67–0.96). The findings of this study reinforced the existing evidence for the adverse effect of child marriage on maternal health-seeking behaviors. Women’s restricted access to household resources, limited autonomy in decision-making, social isolation, and the dominant power of husbands and mothers-in-law may play a role in the findings. Addressing women’s social vulnerability as a barrier to accessing health care may help to increase the uptake of maternal health services.