This experiment was conducted to investigate the effect of dried Leucaena (Leucaena leucocephala) and cassava (Manihot esculenta) leaves on feed intake, milk production, and milk composition of Holstein Friesian x Ankole crossbred cows. Three cows in early lactation, with initial milk production of 4 ± 1.20 kg/day and 359 ± 24 kg average live body weight, were randomly assigned to the experimental diet in a 3x3 Latin square design. Three 15-day experimental periods were adopted (1 to 10-day: diet adaptation and 11 to 15-day: data collection). Cows were fed on a freshly chopped Guatemala grass diet supplemented with 1.25 kg DM of brewers’ spent grain (control). The experimental diets were similar to the control diet differing in the presence of dried Leucaena or cassava leaves, both at the inclusion rate of 20% of the basal diet intake. Total dry matter intake, nutrient intake, milk production, and milk composition showed significant variation among treatments. Cows supplemented with dried cassava leaves had higher total dry matter intake and organic matter intake. Leucaena significantly increased (p < 0.001) daily milk production by 15% compared to cassava (3%). Leucaena had a higher milk fat content (38.44 g), while cassava and the control diet had higher milk protein (38.53 and 38.43 g), lactose (56.79 g and 56.111 g), and not-fat solids (102.41 g and 101.27 g). These results indicate that dried Leucaena and cassava leaves can be used as protein supplements for Guatemala grass basal diet for crossbred cows to improve milk production and quality.