Employee performance is a central variable in employment relations but until recently has received little attention (Austin & Villanova, 1992). Performance has often been confused with activities over which employees have little control such as productivity and output when it is better understood as referring to the behaviours which employees display which are val-ued by their organisation (Campbell, McHenry, & Wise, 1990). Most research on perform-ance has focused on variables relevant to particular occupations rather than identifying broad dimensions of performance which would allow for greater generalisability of results and cross-level inferences to be made. Several general models of performance are reviewed in this article and evidence is presented which supports a two-factor model based on task and citizenship performance (Borman & Motowidlo, 1993; Borman, Penner, Allen, & Mo-towidlo, 2001). Task performance has traditionally been recognised within research and em-ployment relations practice, but the value of citizenship performance has been relatively ne-glected. Citizenship performance appears to contribute as much as task performance to overall ratings of performance, and has substantial causal impacts on organisational outcomes such as customer satisfaction and profitability. The practical and theoretical importance of citizenship performance is reviewed and recommendations for employment relations practice and research are provided.