Selenium, the beneficial or quasi-essential element to higher plants, is an essential micronutrient for animals and humans as well as lower plants. In several countries around the world, about one billion of people are Se-deficient and counteract this problem, e.g., Brazil, Thailand, China and Egypt due to the low inherent Se concentration in soils. Therefore, different Se forms have been used in different crops using foliar and soil application as well as seed priming to increase the Se content in the edible parts of these crops. Due to its physiolocial roles in higher plants, Se has been used in counteracting various abiotic stresses including chilling, freezing, heat, drought, salinity, UV-B and heavy metals. Concerning Se and its interactions with some nutrients like Cu, Mo, Zn and iodine, a very few studies have been published, so further studies are needed. On the other hand, nano-Se and its roles in plant physiology under different abiotic stresses still also need further researches. Therefore, this review will focus on the physiological importance of Se and nano-Se for higher plants under abiotic stresses as well as the interaction of Se with some nutrients including Cu, Mo, Zn and iodine and some heavy metals such as As, Sb, Cd, Cr, Hg and Pb.