A collective efficacy scale is presented and used in 2 experiments that tested the effects of collective efficacy and regulatory framing on concern for body image. In Study 1 (N = 73), participants viewed online video messages from a health campaign that varied in their regulatory frame (promotion vs. prevention), after which they expressed the likelihood that they would discuss it with someone else. In Study 2, participants (N = 307) viewed either a regulatory-framed message or no message, after which they expressed their concern for the issue and their behavioral intentions. Study 2 also introduced moderating variables and addressed potential alternate explanations. Overall, participants who were higher in collective efficacy indicated greater concern for the issue of body image and expressed a greater likelihood to discuss the issue. The messages' regulatory frame also moderated the effect of collective efficacy. Collective efficacy was a stronger predictor in the prevention condition than in the promotion condition, presumably because the promotion frame was more effective in increasing participants' concern and intentions regardless of their sense of collective efficacy.