A differential for a model car includes a housing having a chamber, four notches recessed in a periphery of the chamber and each having a trapezoid section, four blocks received in the notches respectively, a spider having four ends connected with the blocks respectively, four first bevel gears respectively sleeved on the ends of the spider, two second bevel gears received in the chamber and engaged with the first bevel gears respectively, a main gear sleeved on the housing, and two output shafts respectively passing through the main gear and the housing to be connected with the second bevel gears. Thus, the first bevel gears and the second bevel gears can be tightly engaged with each other by means of the arrangement of the spider and the blocks to eliminate the power loss of the model car.