Abstract: One of the major changes in family formation is the increasing tendency for people to enter into co- resident patterning without formalising the union through religious, civil or traditional rites. Despite the implications, this nuptiality behavior which is well documented in the more developed regions, has received negligible scholarly attention in Africa. Using three ranks of DHS surveys (1998-2014) in twelve countries, this study examined the levels, trends, individual and contextual factors associated with consensual union in West Africa. Descriptive results showed a rising trend in consensual union in the sub-region. Multilevel logistic regression analysis suggests that individual-level factors associated with consensual union included education, spousal age gap, second and higher order union, premarital birth, age at first sex, number of sons among others. Contextual predictors were community poverty level, proportion of educated women and proportion of divorced and separated women. Given the health and welfare implications of consensual union, the findings underscore the need for policies and programmatic interventions to protect women in consensual unions, and to extend the benefits of formal marriage to consensual union in case of break up.