The ability to generalize verbs to new examples of previously labelled events demonstrates an implicit understanding that verbs are representative symbols of categories of events. The present study examined when and how very young children generalize familiar verbs to novel events by using the preferential looking paradigm. Overall, 24 children aged 1;8 and 25 children aged 2;2 demonstrated their understanding of the verbs kick and pick-up by looking significantly longer at the target events on control trials. Additionally, children aged 1;8 with the largest expressive vocabulary generalized the same verbs to actions with different agents, but not to actions differing in outcome or manner of action. In contrast, children aged 2;2 consistently extended familiar action verbs to other actions differing in agent or manner, regardless of the size of their expressive vocabulary. These findings were not due to the saliency of any of the actions used and are interpreted in terms of representational change consistent with the acquisition of lexical learning principles.