In this article we scrutinise previous (empirical) research on legitimate use of force by the police with a focus on methodology. First we describe some definitional challenges each police scholar in this domain is confronted with. Secondly, we consider the strengths and weaknesses of different research methods in relation to the study of police use of force. We examine the following five methods: (1) studying official records, (2) survey-research, (3) observational studies, (4) interview methods and (5) mixed methods. Although we did not focus on the research results, we also found an important gap in research on police use of force. We determined that the police officer’s perspective on and experiences with use-of-force incidents are mostly neglected. Based on that finding, at the end of the article, we will introduce our own research project on how Belgian police officers think about the legitimate use of force and how they handle use-of-force incidents. While referring to the results of our methodological review we reflect upon the best-suited research design for our study.