The objective of this study was to evaluate the inclusion of increasing levels of citrus pulp in horse diets by investigating nutrient digestibility and the diet carbohydrate fractions, as well as to evaluate the correlation observed between the studied digestibility coefficients. Five adult horses were used. The horses were housed in individual stalls and had approximate ages of 3.5 years and live weights of 492.5 ± 44.5 kg. The experimental diets were formulated to meet the animals’ requirements for maintenance, establishing a roughage-to-concentrate ratio of 60:40 with the coast-cross hay as the roughage. The formulated concentrates contained increasing inclusion levels of citrus pulp (0%, 7%, 14%, 21%, and 28%). No effect of the diets was observed (p> 0.05) on the coefficients of digestibility of dry matter, organic matter, crude protein, ether extract, nitrogen-free extract, and non-fibrous carbohydrates; however, there was an effect (p< 0.05) on the soluble carbohydrates,y= 66.298 + 0.3724x. Citrus pulp may be used in horse diets at up to 28% concentrate. Citrus pulp is a safe energy source and benefits the digestibility of the nutrients and the carbohydrate fraction (both the fibrous and non-fibrous fractions) of the diet.