Production performance of lactating Nili Ravi buffalo can be improved with feeding of high rumen undegradable protein (RUP) and calcium salts of fatty acids (Ca-FA). Sixteen multiparous lactating Nili Ravi buffaloes were arranged in a 4×4 Latin square arrangement with (mean ± SD) 11.2±0.76 kg/d of milk yield, 6.41±0.23% milk fat, 583±26 kg of body weight (BW) and 161±24 days in milk (DIM). The dietary treatments were: (1) LPLF-low RUP low fat (2) LPHF-low RUP high fat (3) HPLF-high RUP low fat and (4) HPHF-high RUP high fat. The designed diets provided low and high levels of RUP (27.4% and 38.6%) with low (3.5%) and high fat (4.9%). The duration of each period was 21 days and milk sampling was done twice weekly. Statistical significance among treatment means was evaluated using a p-value of ˂ 0.05. Increasing the RUP and fat supplies increased periodic BW and DMI (P ˂ 0.01) with no interaction effect of RUP × fat (P = 0.51) on BW. Milk yield was increased by 3.8% and 14.0% by increasing RUP and fat supplement respectively. The RUP × fat interaction indicated that increase in milk yield was 51% higher when fat was supplemented with low RUP compared with the high RUP diet (RUP × fat, P < 0.01). Milk fat content was increased with the supplementation of fats by 22.0% and milk fat yield by 39.0% (P < 0.01). Milk protein content and yield increased with the increasing RUP level by 10.8% and 15.7%, respectively. Milk lactose yield increased by 5.8% and 17.0% with increasing RUP and fat levels, respectively (P < 0.01). Feed, nitrogen, and milk efficiencies including 4% fat corrected milk (FCM), energy corrected milk (ECM) and milk energy output were increased (P ˂ 0.01) with HF and HP treatments. Plasma urea nitrogen decreased with HP diet compared with LP diet (P ˂ 0.01), whereas the emission of enteric methane was decreased in HPHF group (P ˂ 0.01). In conclusion, the RUP fraction of 38.6% in concentrate and 300 gram of Ca-FA per animal per day increased the production performance of lactating Nili Ravi buffalo, whereas milk fat increased with fat supplementation and milk protein increased with high RUP supplies.