Educator evaluation is described in the literature as those systems in place used to supervise educator excellence as well as to maximize and foster teacher capacity. There have been many changes within the last five years in the Massachusetts educator evaluation model, now called the Massachusetts Model System for Educator Evaluation. Once considered a process that was "done to" teachers, it has become a mutual process between the educator and his or her evaluator. School districts are requiring higher levels of accountability, making this process a potentially high stakes one, sometimes causing angst and anxiety for teachers. Evaluation ratings are also now sent to the state, however, it is unclear at this time how Massachusetts will be using this data. Using Hallinger, Heck and Murphy's (2013) "Theory of Action Underlying Teacher Evaluation" framework, along with the Massachusetts Five Step Model System for Educator Evaluation, and an extensive literature review to define the teacher qualities for effectiveness as it relates to self-efficacy, professional relationships and teacher practices, teacher evaluation was studied. This qualitative study explores how the Massachusetts teacher evaluation process supports changes within teacher effectiveness related to teacher work relationships, teacher self-efficacy and teacher practices. Five teacher participants and two principal participants within two different schools and school districts were interviewed extensively, using the Seidman (2013) Three-Interview Series. Through interviews, teacher observation and document analysis, the educator evaluation model was studied to determine if the Massachusetts teacher evaluation process builds teacher effectiveness. The Hallinger, Heck and Murphy (2013) framework cited three outcomes of teacher evaluation: filtering out poor performers, feedback and support and a results-orientated school culture. Two other noteworthy outcomes were determined within this study: self-reflection and stress and anxiety. The three research questions specifically probing to determine if the Massachusetts Model System for Educator Evaluation leads to or supports constructive change in an educator's work relationships, self-efficacy or teaching practices were answered through the constructs of the theoretical framework, comparing it to the outcomes from the Hallinger, Heck and Murphy (2013) framework, weaving it into the Massachusetts Five Step Model System for Educator Evaluation and then synthesizing it with the literature review framework defining the different elements of teacher effectiveness. [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.]