Background. People with diabetes who have poor health behaviours are at greater risk for a range of adverse health outcomes. We aimed to investigate the relationship between health literacy and health behaviour (smoking, alcohol, physical activity, and diet) in people with diabetes. Methods. The study was based on respondents aged 25 years or older from a population-based survey in 2013 who reported having diabetes (n = 1685). Two dimensions from the Health Literacy Questionnaire were used: “understand health information” and “actively engage with healthcare providers.” We used logistic regression to examine the association between health literacy and health behaviour. Results. After adjustment for sociodemographic factors, individuals with diabetes who found it difficult to understand information about health had higher odds of being physically inactive (OR: 3.43, 95% CI: 2.14–5.51) and having unhealthy dietary habits (OR: 3.01, 95% CI: 1.63–5.58). Similar results were observed for individuals who found it difficult to actively engage with healthcare providers. No associations were found between the two dimensions of health literacy and smoking and alcohol consumption. Conclusion. When developing health services and interventions to improve health behaviour among people with diabetes, our results suggest that they may benefit by including focus on health literacy.