The GCC states and Turkey have recently experienced economic growth and played influential regional roles. In tandem, their relationships grew significantly, and Turkey was considered, for a while, as a "strategic partner". Common challenges have made them consider an alliance to balance other powers and threats. However, many emerging issues have turned them into rivals for regional influence on divergent agendas during the last decade. All in all, their relations are dynamic and rapidly changing. Some regional crises were subjects of political agreement and coordination in their early stages, such as the cases in Libya, Syria and Yemen. However, this agreement has diminished and sometimes turned into conflict. Iran's policies have also led to its change from being a factor of agreement to a factor of difference. On the other hand, some tensions, which were major causes of escalation, were resolved or eased, such as the Gulf crisis and the contest over Egypt. These relations affected the whole region, as well as the great powers involved there.Therefore, this book studies the commonalities between the GCC states and Turkey and analyzes their differences. All parties expressed their desire to restore cooperation despite continuing competition on some regional issues. The book proposes some ideas that can be considered to make convergence possible again.