of Evaluating Teachers’ Professional Growth Abstract The ultimate worth of professional development for teachers is the essential role it plays in the improvement of students’ learning. Guskey suggests a model for evaluating professional development that includes five levels of gathering information about professional development and it is hierarchically arranged from simple to complex. To explore increasing levels of sophistication in evaluating professional development from the participants' reactions to professional development, how to evaluate organizational support and change, the usage of new knowledge, skills ,and the outcome of students learning. This research, according to the model of Guskey, bases on the members of county/city instructors as the research objects. In according with the results of investigations, in the part of participants reactions, most teachers can achieve, however, on participants’ learning, organizational support and change, the usage of new knowledge, skills, and the outcome of students learning that have long been neglected . Keyword: evaluation, professional growth, professional development. 52