Because of segregation in neighborhoods and schools, college may provide the first opportunity for many young adults to interact closely with members of different racial and ethnic groups. Little research has examined how interracial friendships form during this period. This article investigates changes in the racial composition of friendship networks in the transition from high school to college and how aspects of the college environment are related to such changes. Interracial friendships increase for whites, decrease for blacks, and show little change for Latinos and Asians. The habits of friendship formation that are acquired during adolescence and features of residential and extracurricular college contexts influence the formation of interracial friendships. The race of one's roommate, the degree of interracial contact in residence halls, and participation in various types of extracurricular activities are most strongly related to the formation of interracial friendships. (Contains 6 tables and 9 notes.)