Researchers have long acknowledged the important role that vocabulary plays in assisting reading comprehension. Because of the importance of vocabulary, it is necessary to determine how to ensure that all students are making adequate vocabulary gains. The research base for the best ways to instruct students in robust vocabulary is strong. The purpose of this study was to determine the necessary amount of robust instruction for students from low socioeconomic backgrounds to make vocabulary gains. The results of the study indicated that additional instruction was beneficial for all students who received it. There are several implications for classroom practice. The conventional wisdom that all students do not learn in the same way may have limited the notion that some students need more of the same. Therefore, teachers must be prepared to provide additional vocabulary instruction for students who do not master the taught words at the conclusion of initial instruction. (Contains 1 table.)