The slow loris does all of its feeding at night, moving stealthily and deliberately through the darkness. As with other lorises, this species is an arboreal feeder that prefers to forage alone.

These animals are omnivorous, eating many different types of plant and animal material. Fruits and gums make up more than 50% of the diet, but insects and small prey items are a valuable food item also (making up about 30% of the diet). Lorises use their acute sense of smell to locate prey in the dark. Because they are larger and more widely distributed than the pygmy slow loris, slow lorises get their protein from a greater variety of meat sources. Apart from insects, they have been known to eat mollusks, eggs, lizards, birds, and even small mammals.

While this species may look very slow, it is capable of short bursts of very rapid movement when catching prey. They lunge at insects by clinging to a branch with their hind legs, then springing forward and snatching their quarry with both hands. They may then hang upside down to eat.