Certain aspects of social behavior help animals make adaptive decisions during encounters with other animals. When mice choose to approach another conspecific, the motivation and preference behind the interaction is not well understood. Furthermore, estrogen and oxytocin are known to influence a wide array of social behaviors, including social motivation and social preference. The present study investigated the effects of estrogen and oxytocin on social preference using aromatase (ArKO), estrogen receptor (ER) α(αERKO), ERβ(βERKO), oxytocin (OTKO), oxytocin receptor (OTRKO) knockout and their respective wild-type (WT) male mice. Mice were presented with gonadally intact vs. castrated male (IC), intact male vs. ovariectomized female (IF), or castrated male vs. empty cage (IE) stimuli sets for five days. ArWT showed no preference for either stimuli in IC and IF and intact male preference in IE, but ArKO mice preferred a castrated male, ovariectomized female, or no preference for either stimulus in IC, IF, IE stimuli sets respectively, suggesting reduced intact male preference. αWT, βWT mice preferred a castrated male, showed no preference, and preferred an intact male in IC, IF