The integration of computational thinking (CT) and computer science (CS) into formal K-12 learning experiences are critical for students to be competent 21st Century problem solvers. Building student competency with these areas is dependent upon educators who have the pedagogical content expertise to integrate CT and CS within their disciplines and impact student learning in the classroom. Thus, as new K-12 CS standards are established, we must ensure that teachers have appropriate resources and support structures that will enable them to meet these new curricular demands. The purpose of this research was to offer practical and scholarly contributions that would support K-12 non-CS teachers' CT integration practices. Thus, two separate but related studies were conducted. Despite a growing recognition that K-12 teachers should be prepared to teach students CT skills across disciplines, there is a lack of valid instrumentation measuring teachers' teaching efficacy beliefs to do so. The first study addresses this problem by developing and validating an instrument that measures in-service teachers' beliefs for teaching CT. The instrument is grounded in Bandura's theory of self-efficacy and the sub-constructs of personal teaching efficacy beliefs and outcome expectancy teaching beliefs. The manuscript reports on the development and validation process which included expert review, cognitive interviews, factor analysis and reliability calculations. The results indicated that the T-STEM CT is a theoretically sound and reliable instrument to measure in-service teachers' self-efficacy for teaching CT. Implications are then discussed of how the validated, theoretically-grounded instrument can further future research on how to prepare current K-12 educators to teach CT. The second study investigated how a cohort of educators at one middle school collectively enacted new leadership roles to promote the school-wide integration of CT and CS through programming. Using an instrumental case study approach, this investigation examined how leadership was distributed as a distinct activity amongst these educators as they worked to promote these innovative pedagogical practices within the culture of the school. Distributed leadership was utilized as the guiding theoretical lens and activity theory as an evaluative lens to determine how these educators coordinated internal and external resources, collegial relationships, and their own professional capabilities to build a collaborative, professional learning environment focused on CT/CS integration across the school curriculum. Data were collected through observations of and interviews with members of the leadership cohort and other school faculty. The findings suggest that a collective and distributed approach to leadership allowed these educators to effectively pool resources that cultivated and built support for this important school-wide professional learning initiative. This research has implications for the integration of CT and CS in the K-12 curriculum, as many states have recently adopted CS education standards and are seeking successful integration models at the school and district levels. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]