The purpose of this study was to verify the effects of a Vocabulary Acquisition Strategy, applied to the Elementary students with learning disabilities (LD) on the Vocabulary Expansion and Self-efficacy. The participants in these study were three children with LD in 6th Grade Elementary School, Goesan Chungbuk. This study was started on March 2th, 2007 until October 28th, 2007 with 28 to 32 sessions. The subjects were tested by a ‘Vocabulary Acquisition Strategy’ tests that developed by Youn Ock Kim(2006) to measure children\'s ability to utilize strategies on vocabulary acquisition. The Vocabulary Expansion and self-efficacy were also measured. The ‘Vocabulary Acquisition Strategies’ applied through 8 steps of strategy teaching, and the researcher examined the effects of the strategy using a multiple baseline design across the subjects. The followings were the results of this study: First, students with LD could reach \'Vocabulary Acquisition Strategies\' learning up to the mastery level. The researcher guided these subjects to pass the Strategy learning processes step by step. He offered positive feedbacks and helped them, to correct their errors. So that, they could master the strategies. Second, the Vocabulary Acquisition Strategies improved the targeted students\' using Vocabulary Expansion method. Third, the strategies improved the students self-efficacy. the students developed their ability to do what is supposed to do. The findings in this study showed that the Vocabulary Acquisition Strategies had positively influenced the Vocabulary Expansion and Self-efficacy of Elementary students with LD. It has some implications that, the future studies employing the Strategy should be designed with wider range of region and more diverse graders. Further, more it is needed to support students in connection with their home in order to maintain the effectiveness of the Strategy. Teachers need to collaborate the parents of the students with LD to help them generalize and use the Strategy continuously.