Self-identity is considered as a useful additional predictor in the theory of planned behaviour (TPB).\ud However, previous research generally assessed the impact of pro-environmental self-identity in relation\ud to single behaviours and no studies considered its potential role in moderating the impact of other\ud predictors on behaviour. The present research used a within-persons approach to examine effects across\ud behaviours and a longitudinal design to assess the moderating role of self-identity in the prediction of\ud intentions and behaviours, controlling for past behaviour. Participants (N ¼ 240) completed Time 1\ud questionnaires measuring TPB constructs in relation to five different pro-environmental behaviours. Two\ud weeks later, participants (N ¼ 220) responded to a questionnaire assessing self-reports of these behaviours\ud during the intervening two-week period. Across pro-environmental behaviours the findings\ud showed that pro-environmental self-identity significantly moderated the impact of perceived behavioural\ud control on intentions and the effect of past behaviour on both intentions and behaviour