A model of relationship commitment previously validated with data from both partners from dating heterosexual couples was tested with survey data obtained from both partners from 304 same-sex couples cohabiting in the United States. The model posits that commitment is influenced by factors that are ordered along a proximal–distal continuum. From most distal to most proximal, these factors are personality traits, support for the relationship from family members and friends, effective arguing, and dependence on the relationship. Of the 25 predicted effects, 23 were significant (p < .05). Findings support the use of the model for understanding commitment processes for diverse types of dyadic relationships.