A tire condition monitoring system includes transmitters that are respectively attached to wheel assemblies of a vehicle Each transmitter includes a power source, a data generating section a storage section that stores a correspondence relationship in which ranges obtained by dividing possible values of the detection value of a traveling state detecting section are respectively assigned to a plurality of specific angles set for the rotation angles of the wheel assemblies, and a transmission control section capable of performing specific angle transmission in which the transmission control section transmits the transmission data from the transmitting section when detecting that the rotation angle of the wheel assembly is any of the specific angles. When performing the specific angle transmission, the transmission control section transmits the transmission data when detecting that the rotation angle is the specific angle that corresponds to the detection value of the traveling state detecting section.