This experiment was carried out in the two successive seasons 2013/ 2014 and 2014/2015 to study the effect of the pre-harvest foliar applications of potassium silicate at concentration of 4 and 8ml/l, potassium thiosulfate at concentration of 1.5 and 3ml/l, and Harvars at concentration of 2.5 and 5ml/l on the quality and storability of sweet pepper fruits (Capsicum annuum L.) cv. Sonar. The obtained results showed that spraying sweet pepper plants with potassium silicate or potassium thiosulphate significantly improved fruit quality parameters at harvest time i.e., fruit weight, lightness and hue angle. Concerning storage experiment, the obtained results indicated that sweet pepper fruits received pre-harvest potassium silicate at a concentration of 4 ml/l effectively displayed sweet pepper fruits with glossy and vivid green appearance, maintained TSS%, and reduced the degradation of ascorbic acid content of sweet pepper fruits during storage at 8°C and 95 % RH for 21 days.