As teachers and building leaders work to help increase student academic achievement, any strategy that will increase student achievement is worth exploring as an option for helping increase academic achievement. Bandura's theory of collective efficacy, in which individuals working together towards a common goal achieve more than if they were working individually and separately. Many popular education related titles tout the benefits of working collaboratively for teachers and many current principal leadership texts also support building collaborative structures for teachers in order to increase academic achievement. Because of the increasing amount of poverty experienced by students, the percentage of students who receive free and reduced lunch may also impact collaboration, academic achievement, and academic growth. This ex post facto, causal comparative, quantitative study attempts to explore the relationship between the amount of collaboration between teachers in a building, the strength of the building leadership, and academic achievement and academic growth. The "Collaborative Teachers" and "Effective Leaders" subsections of the 5Essentials survey is used as a measurement tool for the amount of collaboration between teachers and for effective leadership. Academic achievement is measured by the overall percentile rank of the school in reading and in math by the Northwest Evaluation Association Measures of Academic Progress (NWEA MAP). Academic growth is measured by the conditional growth index also developed by NWEA MAP. Analysis and recommendations are discussed, particularly in terms of the results' impact on academic achievement and growth for all students. The analysis demonstrated that the variance due to collaboration and effective leadership had a very minimal impact on student achievement. It had a slightly stronger impact on student growth. The strongest impact on the variance in achievement and growth was due to the percentage of students who qualified for free and reduced lunch, the marker of poverty. The implications of the research are also discussed as to how they relate to decisions that can be made at the building level as well as implications for decisions made at the broader system level. [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.]