Criteria are an essential component of any procedure for assessing merit. Yet, little is known about the criteria peers use in assessing grant applications. In this systematic review we therefore identify and synthesize studies that examine grant peer review criteria in an empirical and inductive manner. To facilitate the synthesis, we introduce the Scriven Model, which separates each criterion into an evaluated entity (i.e. the object of the evaluation) and an evaluation criterion (i.e. the dimension along which an entity is evaluated). In total, this synthesis includes 12 studies. Two-thirds of these studies examine criteria in the medical and health sciences, while studies in other fields are scarce. Few studies compare criteria across different fields, and none focus on criteria for interdisciplinary research. We conducted a qualitative content analysis of the 12 studies and thereby identified 15 evaluation criteria and 30 evaluated entities as well as the relations between them. Based on a network analysis, we propose a conceptualization that groups the identified evaluation criteria and evaluated entities into aims, means, and outcomes. We compare our results to criteria found in studies on research quality and guidelines of funding agencies. Since peer review is often approached from a normative perspective, we discuss our findings in relation to two normative positions, the fairness doctrine and the ideal of impartiality. Our findings suggest that future studies on criteria in grant peer review should focus on the applicant, include data from non-Western countries, and examine fields other than the medical and health sciences.