However, the transmission mechanisms of oil price shocks to stock returns in GCC markets should be different from those in net oil-importing countries. Second, the GCC markets differ from those of developed and from those of major emerging countries in that they are largely segmented from the international markets and are overly sensitive to regional political events. Finally, GCC markets are very promising areas for international portfolio diversification. Studying the influence of oil price shocks on GCC stock market returns can help investors make necessary investment decisions and for policy-makers regulate stock markets more effectively. .