The purpose of this research, conducted after the 2015 parliamentary election in Turkey, was to investigate the relations of individuals with their local in-group and an extended in-group. In-group favoritism was interpreted using relative deprivation and social identity theories. Participants were supporters of the Republican People's Party, the Peoples' Democratic Party, and the Nationalist Movement Party. After demographic variables were controlled, group-based relative deprivation and group identification predicted the endorsement of extreme bias in favor of the local in-group and extended in-group members. Second, depending on the participant's political party identity, there were significant differences in relations with members of the supported dissident political party and citizens of the Republic of Turkey.