A method and system for controlling application of MU-MIMO. The disclosure provides for considering a device's mobility as a basis to decide whether to provide the device with MU-MIMO service. For instance, a base station could determine which of the base station's served devices are each stationary or moving less than a threshold extent. And on at least that basis, the base station could select each such device to receive MU-MIMO service. Or faced with a choice between devices to receive MU-MIMO service, the base station could compare the devices' speed of movement and could select the devices that have lower speed of movement to receive MU-MIMO service.