This research has made an attempt to measure the efficiency and productivity scores of a large number of banks in the Gulf Cooperation Council region, over the period 1998-2014. In the main the study attempts to find out if there had been significant differences in efficiency and productivity of the banking sector in the GCC before and after the financial crisis of 2007/8. Furthermore, it has aimed to find answer to the teasing question of whether the conventional banks in the region have performed better than the Islamic banks over the entire period of the study. This study offers a novel and comprehensive approach in measuring efficiency and productivity by incorporating the so-called the resource-based view (RBV) into the main body of literature. In doing so, a number of qualitative variables has been identified to represent the intangibles for those non-substitutable, rare capabilities resources which help produce sustainable competitive edge for a firm in a given industry. Using the relevant data for a large sample of banks in the GCC, the application of Data Envelopment Analysis (DEA) has produced a number of interesting findings. At country level, Bahraini and Kuwaiti banks have turned out to be more consistently efficient over time than the banks in the other four states. Furthermore, the examination of the performance of the newly established banks has shown that they have managed to perform better than the old established ones particularly since the financial recession of 2007/8. More specifically, when Islamic and conventional banks were compared, the estimated results showed that there had been no significant differences in efficiency and productivity between the two groups of banks. Nevertheless, the Islamic banks have demonstrated to have performed better since 2007/8. On the whole, it was demonstrated that as most banks exhibited severe decline in their performance immediately after the 2007/8 recession, the majority of such banks have now managed to return to pre-2007 era and a few have even shown much greater performance since 2010/11. Finally, the study concludes that in all cases the findings have suggested that the inclusion of RBV variables has enhanced and improved the relative efficiency scores for all, and that some banks have been able to maintain consistently higher efficiency primarily due to their competitive edge and capabilities.