Background As rapid response has been a key policing strategy for police departments around the globe, so has police response time been a key performance indicator. This scoping review maps and assesses the variables that predict police response time. Methods This review considers empirical studies, written in english, that include quantitative data from which an association between the outcome variable police response time and any predictor can be observed or derived. This review provides both a narrative synthesis as well as what we termed a hybrid synthesis, a novel way of synthesizing a large quantitative dataset which is considered too rich for a mere narrative synthesis and yet does not allow for meta-analysis. Results The search, screening and selection process yielded 39 studies, which presented 630 associations between 122 unique predictor variables and police response time. In order to present the results in a digestible way, we classified these into categories and subcategories. All methodological steps and the findings are made public: https://github.com/timverlaan/prt. Conclusions Most of the conclusion and discussion focuses on lessons learned and recommendations for future research, as it proved hard to draw any definitive conclusions on causal factors related to police response time. We recommend that future studies clearly describe mechanisms, focus on the components of police response time (reporting time, dispatch time, travel time—or a combination of these), attempt to standardize predictors and outcome variables, and we call for more research into reporting time. We conclude this review with a first attempt at deriving a causal model of police response time from the subcategories of predictor variables we observed in the empirical studies included in this review.