A substrate structure for an image sensor module includes a module substrate including a sensor mounting hole, a reinforcing plate on a lower surface of the module substrate, an image sensor chip on the reinforcing plate within the sensor mounting hole, and a reinforcing pattern in the module substrate. The reinforcing plate covers the sensor mounting hole. An upper surface of the image sensor chip may be exposed by the module substrate. The reinforcing pattern is adjacent to the sensor mounting hole and extends in at least one direction.