This paper investigates the impact of the Dubai oil price changes on the stock markets of six GCC(Gulf Cooperation Council) countries. We use weekly data for the period from 2004. 11 to 2016. 10. Unlike Hammoudeh & Choi(2006) who find no direct impact of oil price changes on the GCC stock markets for the sample period from 1994. 2 to 2004. 12, we observe that the Dubai oil price changes have a significant influence on the stock market returns of the GCC countries except Bahrain. The results of correlation analysis show a significantly positive cross-correlation between the Dubai oil price changes and the GCC stock market returns. Also, the empirical analysis using GARCH model indicates a significant mean and volatility spillover from Dubai oil market to the stock markets of the GCC countries except Bahrain. High mean spillover effect exists for the stock markets of Qatar and Saudi Arabia, and UAE, Oman, and Kuwait form a next order. In addition, considering the negative relationship between the oil price and the U. S. dollar index, we reexamine the GARCH model by using the dollar-weighted oil price changes, and find a consistent result. These results, which are different from extant literature, seem to be resulted from the improved efficiency of the GCC stock markets accompanied by their progressive openness and growing liquidity over time.