This study examined the extent to which the role of the assistant principal is perceived to include instructional leadership behaviors. Specifically, this study compared the perceptions of instructional leadership practices of elementary, middle, and high school assistant principals from the perspectives of assistant principals, principals, and teachers. A nonexperimental comparative design was used. Quantitative data were collected via a version of the Principal Instructional Management Rating Scale that was adapted for application to assistant principals. Analysis of variance, independent-samples t-test, correlation, and nonresponse bias analysis were conducted. Effect size and standard error were calculated. Results indicated that the mean scores given by principals were the highest given by any of the three role groups and those given by teachers were the lowest including the lowest seven mean subscale scores among all role groups. Analysis of variance and t-test results of survey responses indicated that, though statistically significant differences were identified regarding school level, gender of the assistant principal, and role of the rater, no practical differences were found. Results further indicated that there was a negligible relationship between experience and ratings of assistant principal instructional leadership. Recommendations include those related to suggestions for continued research on this topic as well as implications for the practice of instructional leadership for assistant 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.]