The objectives of this study are: 1) to investigate and compare the impact of research and development expenditure of the various funding sources comprising business enterprise, college and university and other funding on economic growth using panel quantile regression technique; and 2) to compare the importance of research and development expenditure on economic growth between developed country, developing country and least developed country by using panel data from 70 countries during the period of 1996 to 2012. The sample countries are divided into the groups with level of development according to classified by The United Nations. The results show that; the dominant research and development expenditure on economic growth of the developed country is only the research and development expenditure of business enterprise funding, the positive impact on economic growth and impact diminishing when the economy expands. For the developing country, the dominant research and development expenditure on economic growth is only the research and development expenditure of other funding; including government, private non-profit, abroad, and not specified. It also has the positive impact on economic growth and impact diminishing when the economy expands. However, for the least developed country, none of the research and development expenditure of various funding source affect to economic growth in all cases. Therefore, it is predicated on the different type of research and development funding affects to economic growth of the development country’s group differ.