The generalization of attitudes toward individual outgroup members into attitudes toward the outgroup as a whole can affect intergroup relations. However, little is known about the relative strengths of the generalization of negative and positive interpersonal attitudes into attitudes about the outgroup. The unique contribution of negative (disliking) interpersonal attitudes to intergroup attitudes was examined and its strength was compared with the effect of positive (liking) interpersonal attitudes, using cross-sectional (Study 1; N = 733, age 10-12) and longitudinal data (Study 2; N = 960, age 12-13). Disliking uniquely contributed to respondents’ outgroup attitudes. The generalization of interpersonal liking and disliking was about equally strong in both studies. This underpins the importance of examining the effects of both positive and negative intergroup contact experiences on the formation of outgroup attitudes.