Two field experiments were carried out at the Experimental Farm, Faculty of Agriculture, Menoufia University, Shebin El-Kom, Egyptduring 2015/2016 and 2016/2017 seasons to investigate the effect of some plant stimulant substances, i.e control,ascorbic acid (1 g/L), citric acid (1 g/L), humic acid (2 g/L ) and salicylic acid (0.5 g/L) as foliar application on vegetative growth performance (plant height, number of leaves and stems/m2, leaf area/ m2 and total plant dry weight/m2),photosynthetic pigments (total chlorophyll), crude protein % in the plant, forage yield (fresh and dry forage /fed) and seed yield and its components (number of heads/ m2, number of seeds/head, 1000-seed weight, seed weight/head and seed yield/fed) of some Egyptian clover varieties (Serw1, Sakha 4, Helaly, Gemmeiza 1 and Giza 6). The data indicated thatHelaly variety surpassed the other varieties in most growth characters (plant height, number of leaves/ m2, leaf area/ m2 and total dry weight/m2), total chlorophyll, crude protein%, fresh and dry forage yields/fedand seed production (number of seeds/head, seed weight/head and seed yield /fed). However, Gemmeiza 1 variety surpassed the other varieties in number of stems/ m2 and number of heads/ m2. On the other hand, Serw1 variety gave the highest value of 1000-seed weight in both seasons. Foliar application of humic acid (HA) was superior to the other rest stimulant substances in most growth and forage yield characters. However, Salicylic acid (SA) produced generally the highest values of CP% and seed yield and its components. On the other hand, unsprayed clover plants (control) gave the lowest values of characters studied. The interactions between Egyptian clover varieties and stimulant substances were found to be significant for most characters under study.It could be concluded that Helaly variety treated with HA being the most effective combined treatment for maximizing forage yield/fed, while the same variety treated with SA produced the highest values of seed yield/fed of Egyptian clover under the experiment conditions. Seasonal fresh and dry forage yields /fed were significantly and positively correlated with most characters studied except number of stems/m2, number of seeds/head and seed weight/head in the first season and 1000-seed weight in the two seasons. Also, seed yield/fed was significantly positively associated with all characters studied except 1000-seed weight in both seasons.