This research evaluated the effects of acerola pulp residue in the lamb diet on intake, digestibility, ingestive behavior and ruminant fermentation. The treatments involved replacing ground corn by acerola fruit pulp residue at levels of 0, 80, 160, 240 and 320 g/kg DM of the total diet. To evaluate the intake, digestibility, N balance and ingestive behavior of lamb, 25 Santa Inês non-castrated male lamb (average age of 9 months and average initial BW of 35.10 ± 4.96 kg) were distributed in a completely randomized design in metabolic cages for a duration of 21 days. To evaluate the ruminal parameters, five fistulated Santa Inês male lamb (BW of 40 ± 3.70 kg) were distributed in a 5 × 5 Latin square design for 75 days. The dehydrated residue from acerola fruit pulp inclusion in lamb diets did not affect the intake of dry matter (DM), crude protein (CP), effective intake nutrients, CP digestibility, N intake, N fecal excretions, N urinary excretions, N balance, NDF eating ratio, ruminal fluid ammonia nitrogen concentration of lamb. However, there was a linear increase (P <0.05) in NDF intake, time spent eating, N° bolus chewed/day and ruminal pH due to the inclusion of acerola fruit pulp. The inclusion of acerola pulp residue linearly decreased (P <0.05) intake of EE, NFC and TDN; digestibility of DM, EE, NDF, NFC; DM eating ratio, amount (g) of DM chewed/bolus and ruminal fluid protozoa population. The time spent ruminating presented a quadratic increase (P <0.05) and time spent idling and NDF rumination efficiency presented an antagonistic behavior. Inclusion of the dry residue of dehydrated acerola fruit pulp up to 80 g/kg is recommended to replace ground corn in the supplement concentrate because despite it reduces very small protozoa population ruminal and nutrient digestibility, it did not quantitatively affect the concentration of ammoniacal nitrogen although it stimulated rumination, thereby improving ruminal environment.