The purpose of this study was to examine the effectiveness of a vocabulary intervention designed to supplement research-based classroom vocabulary instruction, implemented with students who may be at risk for language and learning difficulties. Participants included 43 kindergarten students who received research-based classroom vocabulary instruction. Students with the 20 lowest scores on the Peabody Picture Vocabulary Test-III administered at pretest received additional small-group supplemental vocabulary intervention. Results of within-subjects comparisons indicated that, overall, at-risk students made greater gains in word knowledge on target words that received the supplemental intervention as compared to words that received only classroom-based instruction. In addition, at-risk students who received the supplemental intervention demonstrated word-learning gains that approached those of their peers who received classroom instruction alone. Implications along with limitations of the current study and directions for future research are discussed.