Increased cases of child abandonment, homeless and street children in developing countries are traceable to proportionate rates of unwanted pregnancies. Such pregnancies impose hardships on households and increased social vices in society. In Nigeria, baby factories are continually being discovered in almost every state, thereby raising concerns about the exposure of women to the dangers of unwanted pregnancies. In order to contribute to the government's efforts to control unwanted pregnancies in Nigeria, this study examined the effects of couples' social characteristics and family planning methods on unwanted pregnancies in Nigeria. We applied the Ordinary Least Squares (OLS) method of regression analysis because of its efficiency and unbiased property in statistical analysis. Survey data from the 2013 and 2018 Nigeria's Demographic and Health Surveys were used in the analysis. Results indicated that the more family planning methods are used in Nigeria, the fewer unwanted pregnancies will occur. Furthermore, the social characteristics of men are more important than those of women in predicting unwanted pregnancies. Based on other findings, literacy campaign in the Northern Nigeria where literacy rate is low, more counselling on the importance of modern family planning, and use of different strategies in population health awareness campaign across the different regions in Nigeria is encouraged.