It is a common claim that mutually exclusive social identities can explain political behavior. Recently, studies have instead examined how individuals themselves emphasize different overlapping social identities and its effect on political behavior. However, few of these studies have examined the importance of overlapping social identities in a homogenous country where there exist no mutually exclusive identity groups. Mutually exclusive identities are likely to affect individuals’ self-conception of identity. Consequently, a homogenous country would be a relevant case to examining the role of identity, without the influence of mutually exclusive identities. For this reason, this thesis examines the relationship between social identity and electoral behavior in a homogenous country, using Tunisia as a case. Drawing on regression models of survey data and ideational analysis, this thesis finds that the political importance of social identities is not dependent on the existence of a mutually exclusive out-group. The logistic regression model demonstrates that those who emphasize a Muslim identity are more likely to vote for the Islamist party, while those who emphasized a Tunisian identity are more likely to vote for the secular party. I develop two causal mechanisms that links identity and electoral behavior. First, individuals tend to vote for the party that are perceived as the protector and supporter of their identity because they want to maintain that identity. Second, identity affects attitudes which in turn affects electoral choice due to the role of ideology.