Four studies examined 3- and 4-year-olds' ability to judge accurately whether they acted intentionally. Children self-initiated action to attain an outcome, or their arm was moved by the experimenter to create an outcome. In Experiment 3, children in both age groups accurately claimed they were agents of self-guided action but not of passive movement. In contrast, in Experiments 1, 2 and 4, children in both age groups found it difficult to deny they intended to bring about the outcome, even though their movement was passive and, in some cases, the outcome was unexpected. They were consistently successful only when exclusively involved in creating one of two outcomes and asked which one they intended (Experiment 4). In sum, 3-and 4-year-olds can distinguish when their movements are self-directed and when they are passive. They are limited, however, in applying this distinction to self-judgments concerning whether they acted intentionally. These findings are discussed with respect to linguistic and cognitive limitations that may influence the role first-person knowledge plays in theory-of-mind development.