The purpose of this study is to determine which of the 10 leadership functions contained in the PIMRS, as identified by Hallinger (1983), are demonstrated by principals in Rio Grande Valley middle schools that received Texas Education Agency distinctions for closing performing gaps, compared to those middle schools in the Rio Grande Valley that did not. The study aimed to determine if there was a significant difference been the principal instructional leadership behaviors at middle schools recognized for closing performance gaps compared to those that were not recognized. The results showed that there did not exist a significant difference between the two groups of principals. [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.]