Abstract: Background and Objective: Water and nitrogen are the two major agricultural inputs that influence the yield and water use efficiency of barley. Kuwait is an arid country that depends on irrigated agriculture and intense fertilization due to its scarce water resources and less fertile soil. Studies on the interactive effect of water and nitrogen, the two limiting sources, on barley yield and water use efficiency are little. Therefore, the main objective of the study was to investigate the combined effect of different irrigation and nitrogen treatments on the yield, yield components and water use efficiency of fifteen different barley genotypes under an arid environment. Materials and Methods: The study determined yield, yield components and water use efficiency in 15 different barley genotypes subjected to three different nitrogen fertilizer application rates (0, 50 and 100 kg N ha–1) with two different irrigation treatments (100 and 75% ET) under arid conditions. Results: The nitrogen treatments significantly increased the crop yield and water use efficiency of barley. However, it did not vary significantly between 75 and 100% irrigation treatments. Moreover, 50 and 100 kg N ha–1 nitrogen treatments did not present a significant change in the water use efficiency under the deficit irrigation of 75% ET. Conclusion: Thus, the study implies feasibility of improving barley yield as well as water use efficiency through reduced water and fertilizer use by employing 75% ET irrigation with 50 kg N ha–1 fertilization in arid lands.