<p>The ability to develop time-based event expectations is a crucial factor in anticipatory behavior. This study aimed to investigate the time-based event expectations across different developmental stages. Four distinct age groups were compared: children (mean age = 8.8 years, <i>n</i> = 19), adolescents (mean age = 13.1 years, <i>n</i> = 17), young adults (mean age = 22.8 years, <i>n</i> = 20), and older adults (mean age = 68 years, <i>n</i> = 24). Participants completed a binary choice reaction time task in which short (1000 ms) or long (3000 ms) durations of a visual cue (the foreperiod) predicted the direction of a centrally presented arrow with a probability of 0.9. Results revealed that adolescents and older adults responded more quickly to frequent foreperiod–target combinations compared to infrequent ones, demonstrating their ability to form time-based event expectations. In contrast, children and young adults did not show this ability. These findings suggest that the capacity to form time-based event expectations varies across developmental stages, which may result from the influence of the specific design of the study.</p>