Provided are an in-vehicle wireless communication apparatus, a wireless communication system, a wireless communication apparatus, and a vehicle control method configured to realize prompt external control of a vehicle. An in-vehicle wireless communication apparatus according to the present embodiment includes a wireless communication unit configured to perform wireless communication with an out-of-vehicle apparatus installed outside the vehicle, and a processing unit configured to perform processing related to communication, and the processing unit transmits information regarding a data format of control data to be output to an in-vehicle network by an in-vehicle control apparatus that controls the vehicle, to the out-of-vehicle apparatus using the wireless communication unit, receives data transmitted from the out-of-vehicle apparatus using the wireless communication unit, the data including control data having the data format, and outputs the control data included in the received data to the in-vehicle network.