Field experiments were conducted during the 2019 and 2020 seasons at The Experimental Farm of Sakha Research Station, Kafr El-Sheikh, Egypt, to study the impact of different irrigation regimes, potassium silicate on growth, grain yield, and water productivity of some rice genotypes. The experiments were laid out in a strip-split plot design, with three replications. The vertical plots contained four irrigation regimes, i.e., irrigation every 4-day (I1), alternate 4-day on and 4- (I2),6- (I3), and 8- (I4) days off. However, the horizontal plots consisted of four potassium silicate rates, namely, 0, 1, 2, and 3 % potassium silicate. Meanwhile, the sub-sub plots consisted of three rice genotypes (Sakha 108, Giza 178, and Egy-Kor 27). The main results revealed the growth characteristics, grain yield, and its components were significantly decreased with increasing period from I1 up to I4. The potassium silicate at 3% followed by 2 % registered high values of the study traits. Giza 178 had the highest values of the study traits except for panicle length, panicle weight, and 1000-grain weight which recorded the highest value with Sakha 108.  Irrigation every 4-day consumed the highest amount of irrigation water while the lowest amount was received by I4. The treatment I3 irrigation recorded the highest water productivity as compared to other treatments. Generally, under the same conditions, it is possible to cultivate Giza 178 rice cultivar and alternate irrigation as 4-day on + 4-day off with spray 2 % of potassium silicate for highest grain yield and acceptable water productivity.