The present study explores the impact of nonviolent communication (NVC) intervention on advantaged group members’ actual participation in collective action on behalf of disadvantaged outgroups, also known as solidarity‐based collective action (SBCA). It also examines the mediating role of hope and empathy in this process. Using an experimental longitudinal field study in the context of the Israeli–Palestinian conflict, Jewish Israelis (N = 220) were randomly assigned either to an NVC or to a control condition. Results indicated that, relative to the control, participants in the NVC condition showed an increased tendency to engage in activities that are considered part of SBCA 6 weeks after the intervention. Furthermore, the NVC intervention affected both hope and empathy by maintaining higher levels of hope 6 weeks after intervention and by increasing empathy immediately after intervention. Yet hope, but not empathy, mediated the effect of the NVC intervention on participation in SBCA. Theoretical and applicable implications are discussed.