In a longitudinal study (N = 54), we investigated the developmental relation between children's implicit and explicit theory of mind and executive functions. We found that implicit false belief understanding at 18 months was correlated with explicit false belief understanding at 4 to 5 years of age, with the latter being closely related to second-order false belief understanding at 5 years of age. Also, replicating a number of studies, explicit first- and second-order false belief understanding, in contrast to implicit false belief understanding, were related to executive functioning. This indicates that executive functions play a role in standard explicit false belief tasks, but not in implicit false belief understanding. We argue that spontaneous, implicit false belief understanding does not require conscious control, whereas explicit false belief understanding is based on conscious, reflective processing. In sum, we suggest a developmental enrichment account of theory of mind development, with belief processing becoming increasingly reflective and controlled with advancing age.