Background: Male partner involvement during the postpartum period is an effective intervention to improve maternal as well as newborn health outcomes. There is a connection between involving male partners and increased uptake of maternal health services including postnatal care services. Despite this, male partner involvement in their spouses’ utilization of postnatal care service is not explored in Ethiopia including the study area. Objective: The aim of this study was to assess male partner involvement in postnatal care service utilization and associated factors in Motta district, North West, Ethiopia, 2020. Methods: A community-based cross-sectional study was conducted from March 17, 2020, to 30, 2020 among male partners whose wives gave birth in the last twelve months in Motta district. A systematic random sampling technique was used to get the total sample size of 612 participants. A pre-tested structured questionnaire was used to collect data. Data entry was carried out using Epi data version 3.1and exported to Statistical Package of Social Science version 23.0 for analysis. Bivariable and multivariable logistic regression analyses was employed to estimate the crude and adjusted odds ratio with a confidence interval of 95% and a P value of less than 0.05 considered statistically significant. Results: The overall male partner involvement in postnatal care service utilization was 20.8% with 95%CI (17.57%, 24.11%). Urban residence [AOR=2.42, 95%CI= (1.36, 4.30)], primary and secondary education [AOR=2.20, 95%CI= (1.04, 3.97) & AOR=1.38, 95%CI= (1.04, 5.14)], good knowledge on PNC service [AOR=2.34, 95%CI= (1.38, 3.97)], good knowledge on danger signs and complications [AOR=2.39, 95%CI= (1.38, 4.14)], favorable attitude [AOR=2.61, 95%CI= (1.55, 4.39)], distance [(AOR=2.35, 95%CI=1.30, 4.26)] and waiting time [(AOR=2.40, 95%CI= (1.44, 4.01)] were significantly associated with male partner involvement in postnatal care service. Conclusion and recommendation: The magnitude of male involvement in postnatal care service utilization was low as compared to other studies. Community-based awareness creation through health education by using mass media and campaigning should be provided to raise their involvement, knowledge, and attitude.