Two experiments were conducted to investigate the influences of outcome and negligence on moral judgments of accidental actions, and hence their roles in the explanation of moral luck. In Experiment 1 (N = 300), two previous studies were replicated in which an agent armed with either a bat or a gun (to manipulate negligence) unintentionally killed a suspected intruder who turned out, luckily, to be a burglar, or unluckily, a family friend (to manipulate outcome). In response to an online questionnaire, participants made moral judgments of punishment, blame and wrongness and rated the agent’s negligence and intentionality. The effects of both outcome (victim) and negligence (weapon type) IVs were slight, whereas perceived negligence had a substantial impact on all three judgments. In Experiment 2 (N = 241) the potential influence of both outcome and negligence was raised by increasing the contrasts between conditions: the agent was armed or unarmed, and the suspected intruder was harmed or unharmed. Perceived negligence again had a substantial impact on all three judgments, but now outcome, too, had a strong and direct effect on punishment judgments. These findings indicate that outcome effects on blame and wrongness judgments of accidental agents result primarily from the differential attribution of negligence: agents are considered more negligent – and hence more culpable – when outcomes are worse. In contrast, high levels of punishment are usually assigned when, and only when, the accidental agent is considered negligent and the outcome is negative. We discuss the implications for the interpretation of previous findings of strong outcome effects, and whether these effects, and therefore moral luck, are best explained by hindsight bias or by more rational updating of moral judgments.