The role of vocabulary knowledge in supporting students' comprehension and understanding of their content-area reading is critical. This article explores how content-area teachers can help students become aware of, understand, and apply generative knowledge about English words to grow and develop their vocabularies. Generative vocabulary instruction builds on the fact that most words in English are formed by combining meaningful word parts. Teachers can address this generative aspect directly, modeling and guiding students' developing understanding of this productive aspect of words. A generative emphasis supports more efficient and engaging vocabulary learning of both content vocabulary and general academic vocabulary. Guidelines for teaching vocabulary generatively are provided, as well as effective resources for supporting teachers' selection of and information about words and word parts. (Contains 5 figures.)