We examined the influence of the lexical and grammatical aspect of events on pronoun resolution in adults (18 to 23 years, N = 46), adolescents (13 to 14 years, N=66) and children (7 to 11 years, N=192). Participants were presented with 64 two-sentence stimuli: the first sentence described events with two same gender protagonists; the second began with a personal pronoun and described a status that could be attributed to either protagonist. Participants recorded to whom the pronoun referred, in a booklet. For all groups, Subject resolutions were more likely for events (a) without endpoints relative to those with endpoints, and (b) described as ongoing rather than completed, but this latter influence was restricted to events with endpoints for adults and adolescents. The findings provide support for the Event Structure Hypothesis of pronoun resolution (Rohde, Kehler & Elman, 2006) and provide new insights into the development of pronoun resolution.