OBJECTIVES: Unhealthy behaviour is more common amongst the deprived, thereby contributing to health inequalities. The evidence that the gap between intention and behaviour is greater amongst the more deprived is limited and inconsistent. We tested this hypothesis using objective and self-report measures of three behaviours, both individual- and area-level indices of socio-economic status, and pooling data from five studies. DESIGN: Secondary data analysis. METHODS: Multiple linear regressions and meta-analyses of data on physical activity, diet, and medication adherence in smoking cessation from 2,511 participants. RESULTS: Across five studies, we found no evidence for an interaction between deprivation and intention in predicting objective or self-report measures of behaviour. Using objectively measured behaviour and area-level deprivation, meta-analyses suggested that the gap between self-efficacy and behaviour was greater amongst the more deprived (B = .17 [95% CI = 0.02, 0.31]). CONCLUSIONS: We find no compelling evidence to support the hypothesis that the intention-behaviour gap is greater amongst the more deprived. STATEMENT OF CONTRIBUTION: What is already known on this subject? Unhealthy behaviour is more common in those who are more deprived. This may reflect a larger gap between intentions and behaviour amongst the more deprived. The limited evidence to date testing this hypothesis is mixed. What does this study add? In the most robust study to date, combining results from five trials, we found no evidence for this explanation. The gap between intentions and behaviour did not vary with deprivation for the following: diet, physical activity, or medication adherence in smoking cessation. We did, however, find a larger gap between perceived control over behaviour (self-efficacy) and behaviour in those more deprived. These findings add to existing evidence to suggest that higher rates of unhealthier behaviour in more deprived groups may be reduced by the following: ◦ Strengthening behavioural control mechanisms (such as executive function and non-conscious processes) or ◦ Behaviour change interventions that bypass behavioural control mechanisms.