The purpose of this study is to use statistical evidence to better understand professional development impact and its causal determinants. The study creates a plausible structural equation model (SEM) and tests it. This study uses Abu Dhabi teacher's data drawn from the Teaching and Learning International Survey (TALIS) 2013. A sample of 4,941 teachers from public and private schools participated in the study. The proposed model represented the hypothesis that the latent variable impact of professional development is causally related to other latent variables related to school climate (job/work, school, teacher/student, and attitude), feedback (appraisal, emphasis, and effect), environment, teacher's variables (beliefs and general), student's behavior, and perceived needs for professional development. Results show that professional development impacts are most influenced by feedback effect, school climate (attitude and teacher/student), and student behavior. In addition, variables such as school climate (school), feedback emphasis, and school climate (job/work) have significant effects but indirectly. Teaching in general shows a direct path (effect) to effects; it also shows an indirect effect (through the mediation of feedback effects). The perceived impact is affected also by teacher's gender and age group, and type of school (public or private). Results show that perceived needs, feedback appraisal, and teacher's beliefs do not affect professional development's perceived impact significantly. Teacher categories (gender and age) and school categories (public or private) had significant effects on teachers' attitude with regard to most constructs of professional development.