This study investigated gender differences in counterproductive work behaviour (CWB) among employees in the leasing sector in Lagos State, Nigeria. A total of 187 employees (135 males and 52 females) from seven leasing firms participated using a convenience sampling technique. The Work Deviance Scale by Bennett and Robinson (2000), comprising Organizational Deviance (CWB-O) and Individual Deviance (CWB-I), was used to measure CWB. Independent samples t-tests were employed to assess gender differences. Results showed no significant difference between male (M = 17.25, SD = 8.90) and female (M = 17.31, SD = 8.93) employees in organizational deviance, t(185) = -0.038, p = .969. Similarly, although females (M = 14.88, SD = 4.18) scored slightly higher than males (M = 13.75, SD = 3.73) on individual deviance, the difference was not statistically significant, t(185) = -1.806, p = .073. Levene’s tests confirmed equal variances for both subscales. These findings suggest that gender does not significantly influence CWB levels within the leasing sector, though practical implications for addressing workplace deviance across genders remain important. The study recommends that organizations in the leasing sector implement holistic behavioural management strategies that are not gender-biased, as findings indicate no significant gender differences in counterproductive work behaviour. Emphasis should be placed on creating organizational cultures that promote ethical behaviour and discourage deviant acts among all employees, regardless of gender.