The purpose of this study was to examine the effects of a rich vocabulary intervention on the comprehension and vocabulary learning of third-grade students with language learning disorders (LLD). The study used a repeated acquisition design (RAD), a single case design involving the repeated delivery of a vocabulary intervention on different sets of five vocabulary words and repeated pre-post measurement of students' comprehension and vocabulary acquisition of the different stimuli targeted each week. Students in the treatment group (n = 3) had three weeks of a baseline comparison phase, where they were taught sets of five untested vocabulary words (n = 15 words), and five weeks of a treatment phase, where they learned sets of five tested vocabulary words (n = 25 words). Comprehension was assessed using a passage-level Sentence Verification Technique (SVT) and vocabulary was measured using a nine-point Total Semantic Knowledge (TSK) measure that included an oral definitions component and a receptive vocabulary assessment called Context Test Questions (CTQ). Results indicated no treatment effect on students' comprehension, but a statistically significant moderate effect on vocabulary learning. Two students participated in maintenance phase testing after four weeks without intervention. Testing effects were evident on the comprehension measure at the maintenance phase only. Students scored lower on the vocabulary maintenance assessment than at posttest, but about one point higher than their pretest scores. These results suggest that explicit vocabulary instruction led to immediate improvements in taught vocabulary but not comprehension skills for the third-grade students with LLD in this study. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]