A radiographic image capturing system includes a radiographic image capturing device, a grid, an acquiring unit, and a processor. The radiographic image capturing device includes a radiation detector in which pixels having a sensitivity with respect to radiation or light are disposed two-dimensionally at a predetermined pixel spacing. The grid is placed on a radiation source side of the radiation detector, and includes radiation absorbing members that are disposed at a predetermined spacing. The acquiring unit acquires an inclination angle of the grid, with respect to an array direction of the pixels, with which a spatial frequency of moiré fringes generated by the absorbing members in a captured radiographic image will be equal to or greater than a predetermined spatial frequency. The processor executes predetermined processing for making a relative angle between the grid and the radiation detector the acquired inclination angle.