The purpose of this study was to explore the effect of text-to-speech in a multimedia learning environment on science achievement for students with learning disabilities in reading. The researcher examined how student achievement on unit tests was related to their participation with the experimental treatment. A secondary purpose of the study was to determine whether students prefer the combination of digitized audio and text, or text alone. The researcher used a quasi-experimental, counter-balanced, post-test only design for the study. Qualitative information was collected using post experiment individual and small group interviewing techniques. The sample used in this study was selected from students enrolled at The Forman School, a private school specializing in the education of students with learning disabilities. Specifically, the sample consisted of students with dyslexic reading problems. This independent school is located in Connecticut and currently uses multimedia in daily instruction. The sample consisted of 22 students enrolled in life science classes. The students' ages ranged from 13-19 years and the grade levels ranged from 9-12. Intact, pre-grouped students were randomly assigned to the experimental groups. The main thrust of the study was to examine the effect on achievement of the type of instruction (with and without text-to-speech synthesis) applied. The experimental group consisted of students who received modified multimedia instruction (treatment), including the text-to-speech synthesis. The control group consisted of students who received standard multimedia instruction; a series of texts and graphics without text-to-speech synthesis. Both lessons were identical in content and appearance, with the exception of the text-to-speech synthesis modification. / Ph. D.