Abstract: Saline-water drip irrigated sorghum varietal response to limited available soil water in dune sand was assessed using salinity response function. In a randomized complete block design three sorghum varieties (Local sorghum, BK 16 and EC 90) were grown with drip irrigated saline-water, at four salinity levels (5.47, 7.32, 9.38 and 12.50 dS m-1) and with quality water of 0.11 dS m-1 serving as the control. Four salinity response models were used to assess their ability to discriminate salinity-induced grain yield differences under limited available soil water. Response analysis indicated the four models were equally good in fitting that the grain yield data, but the modified discount model produced the consistently the best fit. Analysis of the data indicated that the impact of salinity stress on varieties was best discriminated by the parameters salinity threshold (Ct), Salinity Tolerance index (ST-index) and the salinity at which 50 % grain reduction (C50) occurred. The analysis indicated that the variety BK 16 was the most tolerance to salinity stress.