The main aim of this study was to determine the factors which influence caterers' hand hygiene practices using social cognitive theory. One hundred and fifteen food handlers from 29 catering businesses were observed carrying out 31,050 food preparation actions in their workplace. Caterers subsequently completed the Hand Hygiene Instrument (HHI), which ascertained attitudes towards hand hygiene using constructs from the Theory of Planned Behaviour (TPB) and the Health Belief Model. The TPB provided a useful framework for understanding caterers' implementation of hand hygiene practices, explaining 34% of the variance in hand hygiene malpractices (p < 0.05). Five components were identified as significant predictors of hand hygiene malpractices: attitudes, subjective norms, descriptive norms, perceived behavioural control and intention (p < 0.05). Thus, suggesting that hand hygiene practices cannot be improved solely through the provision of information to individuals. Effective interventions may need to focus on changing the organisational food safety culture.