Three studies examined whether a social norm message (SNM) to Girl Scouts who had completed an energy conservation program would impact behavior and attitudes. Studies 1 and 2 were conducted with girls recently completing the program, study 3 was conducted with girls completing the program one year earlier. Results suggest that the SNM may impact postprogram energy conservation for participants already dedicated to conservation (study 1), but only when introduced soon after the program ends (study 3). While outcomes are suggestive, this is the first study we know of regarding the impact of SNM on adolescents’ energy conservation.