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 achievement of Korean language and self-efficacy. The participants in the study were three children with LD in 5th grade in an elementary school, Dangjin Chungnam. This study started on April 2th, 2007 and ended on November 23th, 2007 with 27 to 33 sessions. The subjects were tested by the Vocabulary Acquisition Strategy tests that developed by Youn Ock Kim (2006) to measure children\'s ability to utilize strategies on vocabulary acquisition. The achievement of Korean language and self-efficacy were also measured. The Strategy was applied through 8 steps of strategy teaching and the researchers 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 above the mastery level. We guided the subjects to pass the Strategy learning process step by step and offered positive feedbacks and helped them correct their errors. So they could master the strategy. Second, the Strategy impacted positively on the targeted students\' the achievement of Korean language. Third, the strategy also impacted on the self-efficacy of the students. It has some implications that the future studies employing the Strategy should be designed with wider range of region and more diverse graders. Further, it is needed to support students in connection with home in order to maintain the effectiveness of the Strategy.