Abstract: The Late Cenozoic geodynamic evolution of Simav (Kütahya) and surroundings was determined by datingactive tectonic structures in the region (Simav Fault and Simav Detachment Fault) and granitic andvolcanic rocks of the Eğrigöz Magmatic Complex. Additionally it was revealed that the currently normal Simav Fault, in previous periods acted as a strike-slip fault according to dating studies of fault planesand field observations. Dating of the fault planes along the Simav Fault determined that initiation of theSimav Fault occurred in the interval between 19.3-26.1 Ma. In this period the Simav Fault demonstratedstrike-slip fault behavior in a compressional regime. The results of dating studies of the Eğrigöz andKoyunoba Plutons (21.9-26.3 Ma) reveal that the unroofing of these plutons was related to the SimavDetachment Fault (20.0-27.4 Ma). Additionally the presence of volcanism in the time period was identified(7.1-21.3 Ma). The Simav Fault which displayed previous strike-slip character currently has listric normalfault behavior after a tectonic regime change in the Plio-Quaternary. The transition from extensionalcompressional regime to a regional extensional regime and cause of the tectonic regime change is thoughtto be related to the complex subduction process (slab-pull and and roll-back) between the African Plateand Anatolian Plate in the Eastern Mediterranean.