An ignition timing control system for an internal combustion engine is provided to ensure stable combustion without causing misfire or knocking, by properly setting ignition timing in the compression stroke injection mode, thereby improving drivability. The ignition timing control system for the engine, that directly injects fuel into the cylinders and that is operated by switching the fuel injection mode between an intake stroke injection mode and a compression stroke injection mode, includes a fuel injection timing-setting device for setting a fuel injection timing according to an engine speed of the engine and a fuel injection amount, a basic value-setting device for setting a basic value of ignition timing according to the engine speed of the engine and the fuel injection timing, and an ignition timing-setting device for setting ignition timing in the compression stroke injection mode by correcting the basic value according to a detected air-fuel ratio.