In many Western countries, an emerging collaboration between academic researchers and practitioners can be noticed. While different practitioners (e.g. government and policy actors, national security practitioners, social welfare practitioners) are increasingly drawing on external knowledge and expertise to improve their evidence-based policies and practices, academic researchers are involving such actors more closely in their research to benefit the research process. However, despite the various advantages of such cooperation, some ethical and practical issues may arise inherent to their different practices and objectives that could hamper interaction and cooperation between both parties. Starting from personal research experiences, the aim of this contribution is to provide both academic researchers and practitioners with insight into the potential challenges they may encounter during academic-practitioner cooperation and how to overcome them. By providing an overview of good practices and effective strategies, we hope to improve and increase future engagement and interaction between both worlds. This contribution draws upon the research experiences of both authors conducting (criminological) research commissioned by and/or in collaboration with practitioners in Belgium. In the first research project, commissioned by the Flemish government, the disengagement policy in the Flemish prisons was evaluated based on qualitative in-depth interviews, observations and a framinganalysis. The second project, focussing on police officers' ethical decision-making processes, entails a mixed-method design (exploratory phase, online survey, semistructured interviews, systematic social observations, field check by means of focus groups). The challenges of academic-practitioner cooperation relate, amongst others, to the context in which the research is conducted, the researcher's academic independence, the dissemination of the research results and anonymity and confidentiality concerns. The advantages relate, for instance, to the facilitation of (certain parts of) the research process, the knowledge exchange between both worlds, the dissemination of the research results and the networking opportunities. We explicitly aim to give some practical recommendations and good practices concerning how to organize cooperation between practitioners and academic researchers. Cooperation between Extended author information available on the last page of the article