Provided is a radiation imaging system configured to synchronize radiation irradiation with operation of a radiation imaging apparatus. The radiation imaging system includes: an irradiation unit arranged to irradiate with radiation； a detection unit arranged to detect the radiation； a setting unit configured to set an irradiation time at which irradiation of the radiation is to be started； an irradiation control unit configured to control the irradiation unit so that radiation irradiation is executed at the irradiation time； and a detection control unit configured to control the detection unit so that the detection unit is ready to detect the radiation at the irradiation time.
