The purpose of this study was to provide professional development in vocabulary instructional practices and analyze the impact on student achievement. This quasi-experimental study utilized the PLC to curriculum map English/Language Arts state academic vocabulary words in K-4 into each of the four nine-weeks. The first through fourth grade students were pre-and post-tested on the English/Language Arts state academic vocabulary words. Professional development occurred throughout the year regarding best practices for instructing vocabulary, primarily focusing on Marzano's research. In addition, five faculty members observed in classrooms to monitor how academic vocabulary words were used. TCAP and Think Link scores were compared to running records to analyze gains. Finally, the participating teachers completed an anonymous survey regarding the experience. [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.]