Purpose ‐ The purpose of this paper is to assess the performance of banks in countries of the Gulf Cooperation Council (GCC). Design/methodology/approach ‐ Performances of 55 banks operating in countries of the GCC are examined in this study using data envelopment analysis (DEA) and Malmquist productivity index (MPI). When DEA is used, the bank(s) that registered the highest efficiency is used as benchmark and the performance of other banks are evaluated relative to this benchmark. Two outputs and four inputs are employed for the performance measurement. MPI is used to analyze the patterns of efficiency change over the period 2000-2004. Findings ‐ DEA efficiencies are calculated for the year 2004. Results show that only 15 of the 55 banks are rated as efficient under constant returns to scale (CRS) assumption, and all the GCC countries have at least one efficient bank. The analysis using MPI has shown that banks in four of the six GCC countries (Bahrain, Kuwait, Saudi Arabia and the UAE) registered productivity improvements during 2000-2004. The selected banks in Bahrain have shown the highest productivity improvements during this period, while the selected banks in Qatar have registered the highest reductions in productivity during this period. Interestingly, all the countries seem to have registered reductions in productivity in terms of technology change. Research limitations/implications ‐ More banks could not be considered in this study due to non-availability of consistent data. Since performance of banks in more than one country have been compared, we have used a common unit of monetary measurement. Originality/value ‐ This study is first to study the performance of banks in the Middle East, with the exception of a study of selected banks in Kuwait.