The study aims to examine the nature of the relationship and the effect of oil price fluctuations on stock indices in the financial markets of exporting and importing countries. For achieving that, the price of Brent crude oil was chosen as an index from the stock markets in Saudi Arabia, Russia and Iraq as oilexporting countries. While the market index was chosen from the markets of New York, Shanghai and Nikkei as an oil importer. The study came out with a set of conclusions and recommendations. The most important is that the degree of response of stock indices to fluctuations in oil prices was greater in exporting countries than in importing countries.