Two field experiments were conducted at the Experimental Farm of Rice Research Department (R.R.D.), Sakha, Kafrelsheikh, Egypt during 2015 and 2016 seasons. In order to examine the impact of potassium silicate compound as foliar application on the growth, yield and grains quality of Giza 179 rice cultivar. A randomized complete block design (R.C.B.D.) with four replications was used in the two seasons. Foliar applications of potassium silicate, at the rate of control (without potassium silicate), 0.5%, 1.0%, 1.5% and 2.0 % potassium silicate were sprayed twice with the same concentration at 15 and 30 days after transplanting. The studied characters were; chlorophyll content in flag leaf, leaf area index, dry matter accumulation, plant height, no. of tillers per m2, no. of panicles per m2, panicle length cm, panicle weight g, total no. of grains per panicle, thousand grain weight, grain yield ton/ha, percentages of hulling, milling and head rice and silicon content in stems, grains and straw .The results showed that application of potassium silicate caused an increased in growth characters, yield, yield attributes and grains quality of Giza 179 rice cultivar. Potassium silicate at the rate of 1,0% produced the maximum values of chlorophyll content in flag leaf, leaf area index, dry matter accumulation, plant height, number of tillers/m2, number of panicles/m2, length of panicle (cm), weight of panicle (g), grain yield(ton/ha), as well as, hulling, milling, head rice percentages of Giza 179 rice cultivar, while sprayed Potassium silicate at the rate of 1.5 % resulted the maximum total number of grains/panicle and the rate of 2.0% produced the maximum silicon content in stems, grains and straw. All the other parameters showed overlapping results of different potassium silicate levels. According to the previous results, it could be concluded that using potassium silicate as foliar application twice with the same concentration 1.0% at 15 and 30 days after transplanting was the best treatment for improving growth and obtaining the greatest grain yield besides the grains quality of Giza 179 rice cultivar.