A field experiment was conducted during winter season of 2011/2012 and 2012/2013 under sprinkler irrigation at Abdel Monem Riad Village (31 02 N latitude and 30 28 E longitude and altitude of 6.7 m above sea level), El-Bustan area, representing the newly reclaimed sandy soils of West Nile Delta, Egypt. The investigation aims to study the effect of deficit irrigation regimes and rates of potassium fertilizer on grain yield, № of spikesm^-2, 100–kernels weight, kernels№ spike^-1, days to heading (HD), days to maturity (MD), amounts of applied irrigation water, water productivity of three wheat cultivars vs Sakha 93 Giza168and Gemmiza9. The drought tolerance indices e.g. Drought susceptibility index (DSI) and Drought Tolerance Efficiency (DTE%) were considered. The irrigation regimes were represented in main plots, and sub and sub-sub plots were assigned for K fertilization levels and wheat cultivars, and each treatment was replicated 3 times. The important findings could be as follows: -Wheat grain yield and the assessed yield components e.g. № of spikesm^-2, 100–kernels weight and kernels № spike^-1 as well as HD and MD physiological traits were reduced due to the tested DI techniques, comparable with the control. Leaf water potential (-bar) was increased, whereas seasonal applied water was decreased under the assessed DI regimes, comparing with the control. The highest WP values were recorded with DI₅₀ irrigation regime. -The assessed K levels exhibited inconsistent and undistinguished trends as affecting most of the tested parameters. Such findings may be attributed to the improper method of K application. -The drought tolerance indices DSI and DTE% referred that Gemmiza9 is the proper wheat variety to be cultivated under the present experiment circumstances and may be at similar locations as well. -The tertiary interaction of control_{100% ETc} irrigation regime, K₁ level and Gemmiza 9 wheat variety exhibited the highest grain yields i.e. 3.38 and 3.73 tonfed^-1in 1^st and 2nd seasons, respectively.