It has become standard practice for teachers to step into the role of "teacher leaders" and perform a variety of curriculum, instruction and assessment tasks for schools and school districts. The literature regarding these Ohio K-12 teacher leaders, who may perform these tasks in addition to or in lieu of regular teaching assignments, rarely includes a disciplinary focus. In this exploratory, descriptive study the results of a web-based survey containing both closed and open-ended items were used in an inquiry into teacher leaders working with the discipline of science. Data from Ohio teachers responding to the survey were used first to create a standard profile for science teacher leaders. Descriptive statistics and correlations were then performed on quantitative survey data to explore science teacher leader tasks and factors that influence task performance. Analysis of data included descriptions of sense of purpose for their role held by these science teacher leaders. Results indicate that science teacher leaders appear to embrace their role as advocates for science and have great potential for implementing science education reform as well as other science-related school initiatives. Aligning performance, administrative oversight, impact on student achievement and teacher training concerning tasks science teacher leaders are expected to perform would enhance this potential. However, science teacher leaders face challenges to realizing that potential due to ambiguity of their leadership role, the breadth of tasks they tend to perform and lack of alignment between task and outcomes. [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.]