Introduction: The current study examined the extent to which static and dynamic measures of vocabulary and word learning predicted response and identified poor responders to a vocabulary intervention. Methods: Participants were 46 preschool children in classrooms randomly assigned to complete the Story Friends intervention in two cluster-randomized efficacy trials. Children were administered a static measure of vocabulary knowledge and a dynamic assessment of explicit word learning prior to intervention. Vocabulary learning in response to intervention was assessed using a curriculum-based definitional task. Results: Both the static and dynamic measures were significant predictors of vocabulary learning in response to intervention. The dynamic assessment alone predicted 25% of variance in vocabulary learning; the static and dynamic measures in combination predicted 42%. In the responsivity analysis, the dynamic measure provided the best accuracy for a single measure (76%), but the most accurate classification was provided by a combination of static and dynamic measures (79%). The static measure accurately identified 93% of poor responders, whereas the dynamic measure accurately identified 88 %. Conclusions: In this study, both static and dynamic measures predicted preschool children's response to vocabulary intervention and provided a mostly accurate classification of good and poor responders. Additional research can inform the use of dynamic assessment to predict response to intervention and to match children with intense interventions.