Heat stress during plant growing cycle is a critical factor affecting wheat production. The primary objective of this research is to assess the impact of heat stress on key agronomic traits of durum wheat, including grain yield, heading time, plant height, chlorophyll content (SPAD), leaf area index (LAI), normalized vegetation difference index (NDVI), and ground cover ratio. The study was conducted over two consecutive cropping seasons (2019 and 2020) under rain-fed conditions. Twenty durum wheat lines and varieties were used as the research materials. The genotypes experienced significant heat stress from vegatative to reproductive period. Heat stress during plant growth is critical for wheat grain yield and quality but heat stress effects vary between genotypes depending on their stress tolerance level. The study demonstrated the potential of NDVI as a reliable indicator that can be used to evaluate the crop yield performance under temperature stress conditions. This supported by strong relationships between grain yield and NDVI. The association of estimated maximum ground cover (EMC) with earliness indicates that early soil surface closure is related to rapid growth rate. According to ground cover estimations, early ground cover and fast plant growth were related to earliness and plant height, respectively. This study reveals significance of identifying and selecting durum wheat genotypes with good stability under heat stress, aiming to development of heat-tolerant varieties and ensuring more stable wheat production.