The rise of 'HR business partnering' over the last decade has led to an enormous growth in HR competency models. Competencies are believed to provide a mechanism for reinventing traditional HR roles and improving the effectiveness of HR professionals as business partners. But are they effective? The survey and interview evidence presented here suggest that the effectiveness of competency models is disappointing, and they appear to be particularly weak at predicting performance in a business partner role. There are also significant contextual variations in effectiveness based on the degree of change experienced by the HR function, how consistently business partnering is implemented, overall levels of reduction in transactional HR, and the patterns of centralisation–decentralisation of the HR function. The findings highlight the intrinsic limitations of competency models, as well as the powerful influence of contextual factors, and they raise important questions about the future direction of HR business partnering.