This article reports on a 3-year formative experiment involving the implementation and testing of a long-term, multifaceted vocabulary instruction program in fourth- and fifth-grade classrooms in three demographically distinct schools. The quantitative findings indicate that the students, across the 3 years of the project, showed accelerated growth in general vocabulary knowledge in comparison to the large norming sample of a standardized vocabulary test frequently used in research. Additional analyses compared the performance of limited-English-proficient students to that of native English-speaking and redesignated fluent-English-proficient students on the standardized vocabulary test and several researcher-designed assessments. The authors conclude by discussing the significance and the limitations of the findings and the ways that this uniquely successful intervention contributes to research and practice aimed at enhancing elementary-school students' vocabulary knowledge.