In order to study the effects of late-season drought stress and foliar application of potassium silicate on yield and yield components of spring genotypes of canola, a factorial split-plot experiment was conducted in Karaj, Iran in a randomized complete block configuration with three replications for two years of cultivation (2016-2018). The irrigation was performed at two levels in this study, including routine irrigation (control) and interruption of irrigation from the pod formation stage. Potassium silicate foliar application at two levels comprised of 0 and 4 g liter-1 in factorial status in main plots and five Brassica napus L. genotypes including OG×AL, RGS×SLM, DALGAN, RGS003 and RGS×Okapi in subplots. The results showed that the measured properties were affected by the applied treatments. Full irrigation with foliar application in OG×AL genotype resulted in highest seed yield (5620 Kg/ha) and total chlorophyll content (1.71 mg/g.FW) . increased stomatal resistance, leaf proline, leaf soluble carbohydrates and decreased total chlorophyll content and relative leaf water content. Under drought stress conditions, DALGAN and RGS × SLM genotypes had higher yield, which indicates its better performance under stress conditions. Finally, our research demonstrated Potassium Silicate's beneficial effects in improving the drought tolerance of canola plants, particularly at the end of the season. Our study will act as a foundation for attempting new approaches to mitigate drought damage and establish a functional connection between the position of potassium silicate, physiological response, and drought stress tolerance in canola plants.