Some demonstrative embodiments include devices, systems and methods of controlling communications of a multi-radio device. For example, a multi-radio device may include a first radio to communicate over a first wireless network; a first controller to control the first radio; a second radio to communicate over a second wireless network; a second controller to control the second radio; and an interface to communicate signaling messages between the first and second controllers, wherein the first controller is to send to the second controller a request to transmit, the request to transmit indicating a request to allow the first radio to transmit over the first wireless network, and wherein the second controller is to assert a transmit-allowed signal over the interface to indicate that the request to transmit is granted, or to de-assert the transmit-allowed signal to indicate that the request to transmit is denied.