Three studies were conducted to examine the effect of group identification and normative content of social identities on healthy eating intentions and behaviour. In Study 1 (N = 87) Australian participants were shown images that portrayed a norm of healthy vs. unhealthy behaviour among Australians. Participants' choices from an online restaurant menu were used to calculate energy content as the dependent variable. In Study 2 (N = 117), female participants were assigned to a healthy or unhealthy norm condition. The dependent variable was the amount of food eaten in a taste test. Social group identification was measured in both studies. In Study 3 (N = 117), both American identification and healthiness norm were experimentally manipulated, and participants' choices from an online restaurant menu constituted the dependent variable. In all three studies, the healthiness norm presented interacted with participants' group identification to predict eating behaviour. Contrary to what would be predicted under the traditional normative social influence account, higher identifiers chose higher energy food from an online menu and ate more food in a taste test when presented with information about their in-group members behaving healthily. The exact psychological mechanism responsible for these results remains unclear, but the pattern of means can be interpreted as evidence of vicarious licensing, whereby participants feel less motivated to make healthy food choices after being presented with content suggesting that other in-group members are engaging in healthy behaviour. These results suggest a more complex interplay between group membership and norms than has previously been proposed.