Eating behaviour is of particular interest for research focusing on body weight status. However, little is known about the relationships of certain factors, especially social desirability, with self-reported eating behaviour such as cognitive restraint, uncontrolled eating, and emotional eating among young adult males and females. This study aimed to evaluate the relationships between eating behaviour and age, socioeconomic status (SES), physical activity (PA), body mass index (BMI), waist-to-height ratio (WHtR), and social desirability among university students. A cross-sectional study was conducted among 353 university students (59.2% females). Eating behaviour was assessed using the 13-item Three-Factor Eating Questionnaire (TFEQ-13). SES and PA were determined using self-reporting, and the Marlowe–Crowne Social Desirability Scale assessed social desirability. BMI and WHtR were calculated based on measured parameters. Associations between self-reported eating behaviour and other variables were assessed using Pearson’s correlation coefficient and multivariate general linear models. Cognitive restraint was positively correlated with BMI and WHtR in both males (r = 0.174, P = 0.036 and r = 0.194, P = 0.020, respectively) and females (r = 0.239, P < 0.001 and r = 0.165, P = 0.017, respectively), and emotional eating was positively correlated with BMI among females (r = 0.184, P = 0.008). Social desirability was negatively correlated with uncontrolled eating (r = −0.287, P < 0.001) and emotional eating (r = −0.301, P < 0.001) among females. There were no significant correlations between eating behaviour and age or socioeconomic status (P > 0.05). Multivariate analysis showed that, among males, PA had a main effect on emotional eating (ηp2 = 0.044, F = 6.276, P = 0.013). Among females, cognitive restraint was positively associated with PA (ηp2 = 0.034, F = 7.127, P = 0.008) and BMI (ηp2 = 0.038, F = 7.959, P = 0.005), and emotional eating with BMI (ηp2 = 0.032, F = 6.638, P = 0.011). Social desirability had the highest main effect on eating behaviour among females, being negatively associated with uncontrolled eating (ηp2 = 0.077, F = 16.754, P < 0.001) and emotional eating (ηp2 = 0.082, F = 18.046, P < 0.001). This study showed that PA, BMI, WHtR, and social desirability were associated with self-reported eating behaviour among university students. Social desirability bias should be considered when evaluating uncontrolled eating and emotional eating among females.