Silage sorghum has the feature of being an alternative to silage maize in many ways. Considering this feature, the nutritional contents and physical properties of silage maize and silage sorghum were examined. The aim of this study was to compare the physiological and quality characteristics of silage maize and silage sorghum under different irrigation treatments (M100-S100, M80-S80, M60-S60, M40-S40, and M20-S20). This study examined the physiological characteristics (chlorophyll content, plant height, stem diameter, and number of leaves) and quality characteristics (acid detergent fiber (ADF), neutral detergent fiber (NDF), and protein content (HP)) of second-crop silage maize and silage sorghum. Chlorophyll contents were measured before and after irrigation. These measurements showed that irrigation had no effect on the chlorophyll content in both plants in the middle of the growth period, and chlorophyll contents decreased towards the harvest. There was no significant difference between silage maize and silage sorghum plant height values. In the mean values for both years in which the plants were examined, stem diameter values and numbers of leaves were higher in sorghum compared to maize (p<0.05). There was no significant difference between maize and sorghum in terms of their protein contents (8.47% and 8.25%, respectively), acid detergent fiber (ADF), or neutral detergent fiber (NDF) values. In this case, it was seen that sorghum can be an alternative to maize in terms of nutritional quality. The protein contents of both plants decreased from the 100% irrigated treatment to the 20% irrigated treatment (p<0.01). This study will provide valuable information to feed producers and researchers in terms of comparing the physiological and quality characteristics of silage maize and silage sorghum under deficit irrigation conditions.