In Massachusetts public elementary schools, teaching and leadership roles are perceived as mutually exclusive rather than interwoven. Despite credentials that would recognize Massachusetts public elementary school teachers as leaders beyond their classrooms, the leadership frame of reference attests that those who have the position, power and authority to lead (e.g., superintendents, directors, principals) are the leaders of schools and school districts. Because of this, the prospect of an expanded pathway for formal public elementary school teacher-leadership is challenged and there is a dearth of literature pertaining to formal teacher-leadership practices in public elementary schools. This study sought to understand this phenomenon and is based on the following three guiding research questions: 1) How do public elementary school teachers in Massachusetts define and understand formal teacher-leadership in public elementary schools? 2) What are the ways public elementary school teachers in Massachusetts say they perform formal teacher-leadership roles? 3) What are the factors and conditions that public elementary school teachers in Massachusetts believe promote or inhibit them from performing formal teacher-leadership roles in their schools? In total, sixty-six public elementary school teachers participated in the study. This research employed a sequential explanatory mixed-methodology. The analysis of data collected from a survey and follow-up interview uncovered the following findings: (1) Inconsistent structure and opportunities for formal teacher-leadership roles in public elementary schools in Massachusetts leading to varied opportunities and ineffective alignment towards school and district goals, (2) School culture of mistrust and lack of support for formal teacher-leaders or those aspiring to engage in formal teacher-leadership roles, (3) Providing role clarity and release time would increase the effectiveness of those performing a formal teacher-leadership role, (4) Veteran teachers attain organically derived leadership through the trust and buy-in of their colleagues, (5) Professional development to specifically cultivate skills for those in a formal teacher-leadership role is needed, (6) A teacher evaluation system that is specific to the formal teacher-leadership role is needed. The implications of these findings are analyzed and discussed. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]