In our paper, we explore the diversity-performance link in knowledge production and argue it to be the result of two countervailing effects (resource vs. process perspective). Theoretically, we show that the relative strength of the two effects crucially depends on moderating factors that relate to specificities of the knowledge production process, the type of diversity and group interaction. We empirically test our hypotheses based on an original data set of 45 university research groups from different disciplinary fields which are by nature expected to produce new knowledge and are faced with complex tasks. Employing traditional OLS regressions as well as non-parametric LOWESS analyses, our hypotheses are largely born out by the data. In particular, we find a U-shaped relation between cultural diversity and performance in research groups from the humanities & social sciences and a negative link between functional diversity and per-formance in research groups from the natural sciences. As the disciplinary fields proxy different underlying knowledge production processes, the implications of our study can be generalized to other settings and help derive general conclusions for the management of diversity and future competitiveness strategies in knowledge intensive economies.