A driving force control system for a vehicle having a mechanism for changing an engine speed continuously. The driving force control system basically controls said mechanism in a manner such that the engine speed is adjusted to optimize fuel economy. The driving force control system is configured to determine an index representing a demand to enhance agility of behavior of the vehicle based on an actual behavior of the vehicle or an amount of operation carried out by a driver to cause said behavior. An upper limit value of the engine speed of the case in which a drive demand is increased is determined on the basis of the index, and the upper limit value is set to the higher value with an increase in the index representing the demand to enhance agility of behavior of the vehicle.