Bill Goodykoontz of "The Arizona Republic" gave the film three and a half stars out of five, saying, "Bacon can play just about anything, and he's having a good time here as a guy not quite smart enough to keep himself out of trouble, but wily enough to try to dig himself out of it. It's fun to watch." Bruce Demara of the "Toronto Star" gave the film three out of four stars, saying, "Anchored by solid performances and a taut script, "Cop Car" is a tension-filled thrill ride." Brian Moylan of "The Guardian" gave the film four out of five stars, saying, "The movie culminates in a tense, protracted standoff that keeps the audience on edge for way longer than is comfortable. I mean that as a compliment." Todd McCarthy of "The Hollywood Reporter" gave the film a negative review, saying, "A potentially fun premise soon turns into no fun at all in "Cop Car", a seriously imagination-challenged low-end action thriller." Peter Debruge of "Variety" gave the film a positive review, saying, "Watts demonstrates masterful control, pushing right up against the limits of what we can take (even non-parents will be rattled watching the boys mishandling loaded weapons), and yet, at every turn, the screenplay falls short of the picture's full potential, missing opportunities that could have made this a classic."