OBJECTIVES: To examine education differences in five-year weight change among mid-aged adults, and to ascertain if this may be due to socioeconomic differences in perceived weight status or weight control behaviours (WCBs). METHODS: Data were used from the Australian Diabetes, Obesity and Lifestyle Study. Mid-aged men and women with measured weights at both baseline (1999-2000) and follow-up (2004-2005) were included. Percent weight change over the five-year interval was calculated and perceived weight status, WCBs and highest attained education were collected at baseline. RESULTS: Low-educated men and women were more likely to be obese at baseline compared to their high-educated counterparts. Women with a certificate-level education had a greater five-year weight gain than those with a bachelor degree or higher. Perceived weight status or WCBs did not differ by education among men and women, however participants that perceived themselves as very overweight had less weight gain than those perceiving themselves as underweight or normal weight. WCBs were not associated with five-year weight change. CONCLUSIONS AND IMPLICATIONS: The higher prevalence of overweight/obesity among low-educated women may be a consequence of greater weight gain in mid-adulthood. Education inequalities in overweight/obesity among men and women made be due (in part) to overweight or obese individuals in low-educated groups not perceiving themselves as having a weight problem.