##### **Please cite as:** Reimer, N. K., Becker, J. C., Benz, A., Christ, O., Dhont, K., Klocke, U., ... Hewstone, M. (in press). Intergroup contact and social change: Implications of negative and positive contact for collective action in advantaged and disadvantaged groups. *Personality and Social Psychology Bulletin*. ##### **Abstract** Previous research has shown that (1) positive intergroup contact with an advantaged group can discourage collective action among disadvantaged-group members and (2) positive intergroup contact can encourage advantaged-group members to take action on behalf of disadvantaged outgroups. Two studies investigated the effects of *negative* as well as *positive* intergroup contact. Study 1 (*N* = 482) found that negative but not positive contact with heterosexual people was associated with sexual-minority students’ engagement in collective action (via group identification and perceived discrimination). Among heterosexual students, positive and negative contact were associated with, respectively, more and less LGB activism. Study 2 (*N* = 1,469) found that *only* negative contact (via perceived discrimination) predicted LGBT students’ collective action intentions longitudinally while *only* positive contact predicted heterosexual/cisgender students’ LGBT activism. Implications for the relationship between intergroup contact, collective action, and social change are discussed. **Keywords:** *intergroup contact*, *negative contact*, *collective action*, *demobilization*, *LGBT*