Along with globalization and increasing competition, regional development disparities has become a fundamental concern of all the countries. In this context, regional development agencies have been established to effectively reduce regional development distinction and to increase the investments. These development agencies are intended to minimize the unemployment problem in underdeveloped countries as well as other problems. In addition to regional economic development, these development agencies play an important role in both economic growth and development of the country. Regional development agencies first emerged in 1929 after the Great Depression, and the first example of these development agencies were seen in the United States at the Tennessee Valley Authority in 1933. It was not until after 1950’ s that the regional differences became obvious in Turkey. This study examines responsibilities and characteristics of development agencies around the World and discusses their application in decreasing the regional disperaties in Turkey.