Carol Dweck's Mindset Theory suggests that a teacher who has a growth mindset believes that a student's basic qualities are things you can cultivate through effort. Dweck's theory explains that by applying a growth mindset towards children, they begin to change the way they take on challenges in their education (Dweck, 2006). One way that districts can help teachers shape attitudes and create classrooms with positivity is by providing professional development in the theory of growth mindset. The purpose of this study was to examine one suburban Long Island school district's systematic plan of professional development in Carol Dweck's Growth Mindset Theory. This systematic plan was the creation of the district's incoming superintendent, whose vision was to create a community where all students can achieve success by learning how to persevere in the face of obstacles and understand that mistakes are a part of the learning process. In looking at this particular district, we wanted to determine if this school district's designed professional development in the theory of Mindset positively impacted the reading achievement in their special education students, based on ELA scores in grades 3-8. This case study will also examine the impact on teachers who participated in systematic year-long professional development in Carol Dweck's theory of Growth Mindset. Finally, this study looked at what teacher practices are the most observable after professional development in growth mindset. What this study revealed is that although we do see a slight increase of special education students who were proficient on the exam, we cannot for certain say this was solely in part due to the professional development the staff received in Growth Mindset. In regards to the staff perceptions of the effectiveness of the professional development in Growth Mindset, data suggests that the staff of the targeted school district felt the professional development was worthwhile, with many teachers ready to implement, if not already implementing, Growth Mindset practices in their classrooms. Finally, qualitative data showed that there were many observable characteristics of Carol Dweck's Growth Mindset Theory embedded in the observed classrooms. [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.]