Positive cross-group contact can undermine disadvantaged group members' collective action engagement. However, we hypothesised that positive cross-group contact in which an advantaged group member explicitly communicates opposition to inequality between groups ("supportive contact") would not undermine collective action and would be empowering for disadvantaged group members. Study 1 focused on cross-group contact between international students and domestic students at an Australian university. Study 2 focused on immigrants to Canada, and provided an opportunity for a cross-group contact with a Canadian-born individual. The results revealed that supportive contact heightened collective action engagement relative to a number of comparison conditions involving other forms of positive cross-group contact. Increased perceptions of injustice emerged as the key mediator of the relationship between supportive contact and increased collective action engagement.