This study explores the predictive accuracy of the theory of planned behaviour (TPB) in relation to continuation of intentions. Three studies examined the hypothesis that continuation intentions of success and continuation intentions of failure would improve utility of the TPB in predicting and promoting social behaviour. As a new construct, continuation intentions of success and continuation intentions of failure aim to describe people's readiness to continue performance of an activity under conditions that signify successful and unsuccessful progress at behavioural outcomes. As predicted, Study 1 (N = 222, male = 107, female = 115, age = 14.62 yrs, SD = 1.45) and Study 2 (N = 200, male = 101, female = 98, age = 14.29 yrs, SD = .92) showed that continuation intentions of success and continuation intentions of failure contributed to the prediction of physical activity over and above components of the TPB, past behaviour and perceived progress. Study 3 (N = 93, male = 50, female = 42, age = 20.53 yrs, SD = 3.36), a study of food choice, manipulated continuation intentions and showed that participants who formed continuation intentions were more likely to eat five portions of fruit and/or vegetables than participants in a control group. Together, these findings underscore the theoretical as well as practical importance of distinguishing between intentions and continuation intentions, and the need for influence attempts to manipulate continuation intentions.