Purpose: The goal of this study was to determine whether positive treatment effects of a modified constraint-induced language therapy focused on verb production would generalize to unpracticed items and tasks. Method: Four individuals participated in a single-subject treatment design protocol. The treatment involved intensive practice producing verbs in sentences in an informative communicative exchange. Direct treatment outcome was examined by measuring the accuracy of producing practiced verbs in an action description task, a task similar to those used in treatment. Generalization was assessed by measuring production of unpracticed verbs and sentence grammaticality in the action description task and by measuring verb production and sentence grammaticality in 2 relatively unstructured (unpracticed) language tasks. Results: Two of the 4 participants showed a direct treatment effect, producing a greater number of practiced verbs in the action description task following treatment compared with before treatment. All participants improved sentence grammaticality following treatment, although grammaticality was not explicitly targeted in therapy. Generalization to unpracticed, less-structured tasks was variable across the participants. Conclusion: Patterns of generalization may depend on participants' specific language deficits and production characteristics, on the language tasks used, and on the measures used to detect change and assess generalization.