Measuring the efficiency of the Iraqi banking system using data envelopment analysis (DEA) Abstract: This study is concerned by measuring the efficiency of the Iraqi banking system. The importance of study comes from the role of the financial and banking sector In terms of performance of its finance function to transfer capital from surplus units to deficit units to finance investments and thus economic growth. The study uses Data Envelopment Analysis (DEA) method to measure the technical and scale efficiency of the output of banks by adopting the output-orientated approach. The study included a large sample of the banking system in Iraq (36) banks, and the assets of the sample (95%) of the total assets of the banking system, and extended the time limits of study for four years (2011-2014). The study found that the efficiency of the Iraqi banking system is low. Only eight banks have achieved full technical efficiency during the study period, namely four local and four foreign banks, while only four local banks have achieved full scale efficiency. The results of the study also indicate that most of the banks of the sample are working at the stage of increasing returns, which means that they have great capacity to expand their outputs in terms of services and the establishment of new branches