One of the problematic areas in foreign language teaching is regarding to testing. Providing a list of questions in an stressful atmosphere makes learners hate exams; however, they can be in a relaxing position and learn something during the exam. This study is an original master degree dissertation examined the effect of dynamic (a new way of testing) and non-dynamic or the traditional type of assessment on the acquisition of apology speech act among Iranian EFL learners. Speech acts are one of the most functional parts in applied linguistics and the need for and use of apology as one of the speech acts is inevitable in our daily lives. Furthermore, using and understanding apologies in a foreign language is difficult and needs proper instruction and appropriate assessment. To this end, one-hundred forty-three Iranian learners, who were selected randomly, were assigned to high and low groups based on their score in OPT. Then, each group was divided into two DA and NDA groups randomly. Both groups participated in pretest and posttest, six treatment tests during fifteen sessions, and also an instruction part about different apology strategies based on Olshatain and Cohen (1983). DA groups, the experimental ones, received different types of mediation in tests based on Lantolf and Poehner's (2011) scale and their ZPDs. NDA groups, the control ones, were assessed in traditional method. T-test was used to analyze the data, which revealed that DA group significantly outperformed NDA group. The main result of this study showed that dynamic assessment helps learners to improve their apology speech act acquisition. Therefore, the integration of instruction and assessment helps learners find the rules themselves and the teacher helps them if they go wrong. The atmosphere are relaxing and the teacher pays more attention to individuals instead of the whole class at the same time. The findings of this study provide insights to assessment in general and especially in pragmatics. It is in this spirit that this book is written. I would like to take this opportunity to recognize the time and effort devoted by Omid Tabatabaei Ph.D who significantly supervised my thesis. From one step to the next, he not only spent tremendous time reading the successive drafts of this research, but also acted as a truly compassionate person. Without his support, this thesis would have never taken shape. A special mention should also be made to my family in general, who stood by my side in my education and especially in my writing task, but in particular to my parents for their constant support and encouragement for making my life easy and happy.