The purpose of this study was to determine the extent to which tri-weekly evidence-based vocabulary lessons implemented throughout the regular school day would increase kindergarten students' expressive and receptive vocabulary development, thus decreasing the vocabulary gap exhibited between low-income children and their more advantaged peers upon entering kindergarten. The participants in this study were kindergarten students at an elementary school in the Midwest. The students in the control group received their normal vocabulary instruction from the district's adopted reading series. The experimental group students received instruction from the evidence-based direct instruction vocabulary lessons found in Judy Montgomery's "The Bridge of Vocabulary." Data was collected before and after the intervention took place using the Peabody Picture Vocabulary Test, Fourth Edition and the Expressive Vocabulary Test, Second Edition, and was analyzed using an ANOVA to compare growth. Analysis showed that students who received the vocabulary intervention made significantly greater growth in both expressive and receptive vocabulary development than students who received vocabulary instruction from the adopted reading series. More specifically, the students from poverty who received the intervention made significantly greater vocabulary development than the students from poverty who did not receive the intervention. [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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]