The purpose of this study determined if a significant relationship existed between the amount of professional development that teachers participated in and the impact on the classroom instruction that followed. The goal was to study the effect that this had on student achievement in the State of Texas Assessment of Academic Readiness (STAAR) for English 1 and Algebra 1 for students at a large north Texas high school. Testing years for the study included the school years 2013-14, 2014-15, and 2015-16. Additional variables included the work in three areas of teacher professional development over the three-year period. Fourteen teachers, in two subjects, were studied in their implementation of classroom instruction. Particular attention was given to the instructional changes, and the number of hours of professional development in the areas of instruction, technology, and differentiation. Teachers were given opportunities to participate in 18 hours of professional development in all three areas in each of the three years. Teachers were then asked to incorporate the work that they completed each year into their day to day classroom instruction. The goal of the implementation of the professional development in addition to the curricular specifics regarding instruction of state standards was expected to produce increased state scale score marks for the students in the classes. Results of the study indicated success for students in the area of English 1 end-of-course assessment. From the beginning of the study, where student success rates in English state assessment was calculated at 47% overall passing rate, to the completion of the study, where student success was charted at 70% overall passing rate, significant changes were noted. In addition to the improvements made in English I, there were also significant changes made in the approaches to the Algebra 1 assessment. Classroom instructional practices were noted as much improved, and professional learning community collaboration produced significant classroom instructional improvements.