Recent work supports the role of reasoning in third-party moral judgment of harm transgressions. In particular, reasoning may increase the weight of intention in moral judgment of accidental harm, a situation that presumably requires judges to balance considerations about the outcome endured by a victim on the one hand, and considerations about an agent’s intention to cause harm on the other hand. Three preregistered lab-based studies aimed to bring further evidence for the causal contribution of reasoning to moral judgment of harm transgressions using experimental manipulations borrowed from the reasoning literature: time pressure (Experiment 1), cognitive load (Experiment 2), priming (Experiment 3). Participants (N = 178) were presented with short fictitious scenarios in which the agent’s intention toward a potential victim (harmful or neutral intent) and the action’s outcome (victim’s injury or no harm) were manipulated. Participants then reported their moral judgment of the agent’s behavior (wrongness and deserved punishment) and their empathy toward the victim. Overall, we did not find an effect of the reasoning manipulation on judgment severity. Participants were not more severe toward accidental transgressors when reasoning was prevented. The present study does not bring further support to the idea that accounting for intention in third-party moral judgment of harm transgressions may be a cognitively costly process, and we discuss these null findings in light of the moral judgment literature.