The disclosure describes embodiments for reducing adjacent channel interference for wireless vehicular messages. In some embodiments, a method includes monitoring, by an onboard vehicle computer, a channel of a Vehicle-to-Everything (V2X) radio for a V2X message. The method includes determining waveform data describing a waveform that is measured on the channel by the onboard vehicle computer when monitoring the channel. The method includes determining interference data which describes an adjacent channel interference waveform which is measured on the channel by the onboard vehicle computer when monitoring the channel. The waveform includes the adjacent channel interference waveform. The method includes canceling out the adjacent channel interference waveform described by the interference data from the waveform described by the waveform data to generate digital data describing a version of the V2X message that substantially does not include the adjacent channel interference waveform, thereby reducing the adjacent channel interference for the V2X message.