ABSTRACT This experiment was conducted to evaluate the effect of increasing levels of greasy babassu by-product (GBB) effects on ingestive behaviour, physiological parameters and carcase traits. Twenty-eight lambs (20.6 ± 4.1 kg of initial BW) were distributed in a completely randomised design being confined for 60 days. The treatments were GBB inclusion levels (0, 50, 100 and 150 g kg-1, in DM basis) in diets with 20% roughage and 80% concentrate (DM basis). Physiological parameters and ingestive behaviour did not change with the inclusion of GBB in the diets (P > 0.05); however, the time of ruminating tended to decrease as well as the time of ruminating chews per bolus, and number of ruminating chews per bolus (P < 0.10). Additionally, inclusion of GBB did not change the carcase traits and commercial meat cuts (P > 0.05). Thus, the addition of GBB up to 150 g kg-1 in the diet for finishing lambs represents an attractive alternative feed for corn and soybean meal, which does not modify the physiological parameters, ingestive behaviour and carcase traits.