This thesis investigates the nature of the Hellenistic settlements in Smooth Cilicia from the perspective of five multi-period sites that give clear, stratified evidence for architecture and other aspects of material culture. Before the 1990s, such a study would have been impossible. The only excavation project in the region that could have contributed evidence was Tarsus. Otherwise, the Hellenistic period was known only from textual records and some surveys. Now, thanks to excavations at Soli- Pompeiopolis, Sirkeli Höyük, Tatarlı Höyük, and Kinet Höyük, in addition to those at Tarsus, sufficient data for examining the nature of Hellenistic settlements is available. This thesis first examines historical events and geographical features that might have effects on settlements. The main focus, however, is the architecture, its development through the Hellenistic centuries, and the ceramics and other cultural material recovered from stratified deposits. The data used in this study mainly comes from the excavation reports, which are either detailed, as for Tarsus, or, as for the recent excavation projects, short and preliminary. This thesis concludes that the Hellenistic period in the multi-period settlements of Smooth Cilicia was characterized by small towns with simple buildings in contrast with those yielding monumental and impressive structures in Greece, Western Anatolia, or Egypt. Occupation at these sites, except at Tarsus-Gözlükule, had been continuous from the previous Persian period. In the Roman era, most of these settlements were abandoned, to be reestablished at new locations nearby with monumental and impressive structures.