Aim: The main motivation of this study is how to achieve growth that one of the most important stages of economic development. Method: In this study, exogenous growth theories, which accept technological development that includes R&D and innovation as an exogenous factor, and endogenous growth theories, which accept technological development as an endogenous factor in the growth process. Exogenous and endogenous growth theories are respectively examined based on Solow (1956) and Romer (1986) growth models. Results: In fact, although both models accept technological developments as the source of growth, the Solow model cannot explain the source of technological development. A new theory was proposed by Romer (1986) with the idea of completing these shortcomings in the Solow (1956) model. Contrary to the model developed by Romer, the increase in R & D expenditures is not reflected on the growth rates in recent years. This situation causes criticism of endogenous growth theories. Conclusion: Therefore, it is seen that there is still a need for theoretical studies to explain to the differences of development between countries.
Keywords: Economic Growth Theories, R&D, Technological Development