Attitudes and social norms are key social psychological concepts that have often been considered as independent determinants of human behavior. However, questions about the interplay between the two are somewhat of a blind spot in social psychology. In the present research, we test the hypothesis that when an important change in norms is involved, behavioral intentions will be shaped by a discrepancy between personal attitudes and the perceived group norm, that is the perception of other group members’ attitudes. This proposition is tested and supported across three studies in a context of the conversion to organic farming, a behavior indicative of a significant societal and behavioral change. Farmers who did convert to organic farming were those who perceive other farmers to hold less positive attitudes toward this environmentally-friendly practice compared to their own (Study 1a & 1b, N = 1,023). Among conventional farmers, the intention to convert to organic farming is also predicted by a discrepancy between personal attitudes and the perceived group norm (Study 1b). Finally, among agricultural colleges’ students (Study 2, N = 280), the intention to become an organic farmer was influenced by an interaction between attitudes and perceived group norm and not only by independent effects of these two variables. The theoretical and practical implications of these findings for a better understanding of behavioral adaptation in times of social change are discussed.