This study had two main aims. (1) To examine the role of discretionary effort (DE) in the multidimensional performance domain consisting of in-role behaviour (IRB) and organisational citizenship behaviour (OCB); and (2) to assess whether skills and autonomy are important predictors of DE and show variance in common with DE over and above IRB and OCB. A managers/supervisors sample (n = 476) and a sample with both managerial and nonmanagerial employees (n = 424) were employed. Confirmatory factor analyses showed that the three factor hierarchical model was superior compared to three other models tested, indicating that DE is a separate construct to both IRB and OCB but together with these forms part of the performance domain. Regression analysis showed that both skills and autonomy are important predictors of DE; however, only autonomy explained variance in DE over and above IRB, OCB and skills. Together these results add to the construct validity of DE. Implications and suggestions for future research are discussed.