A study was carried out in village Bheaky, District Sialkot. Forty five trees of Acacia nilotica were selected to determine their effect on wheat crop. All the trees varied in diameter and height and were on the southern side of the wheat field. The trees were divided into seven diameter classes i.e. D1 = 20 - 24.9 cm, D2 = 25 - 29.9 cm, D3 = 30 - 34.9 cm, D4 = 35 - 39.9 cm, D5 = 40 - 44.9 cm, D6 = 45 - 49.9 cm, D7 = 50 - 55.9 cm. Effect of Acacia nilotica on crop height was observed upto a distance of 11.0 m. but was statistically non-significant. Similarly the tree size did not have any significant effect on crop height. Above-ground biomass was significantly affected by the distance from the trees. Acacia nilotica reduced wheat biomass yield by 51.69% and grain yield by 55.10% at 1 meter distance as compared to control. The reduction in biomass and grain yield was noted upto 11 meters from the tree trunks. As far as economics is concerned, total loss of grain yield and wheat bhoosa yield was Rs. 359/ha during crop growing period of six months. Where as income from trees was Rs. 1071/- hence net profit was Rs. 712/- per hectare.