A broadcast signal intrusion is the hijacking of broadcast signals of radio, television stations, cable television broadcast feeds or satellite signals without permission or licence. Hijacking incidents have involved local TV and radio stations as well as cable and national networks.

Although television, cable, and satellite broadcast signal intrusions tend to receive more media coverage, radio station intrusions are more frequent, as many simply rebroadcast a signal received from another radio station. All that is required is an FM transmitter that can overpower the same frequency as the station being rebroadcast (limited by the inverse-square law). Other methods that have been used in North America to intrude on legal broadcasts include using a directional antenna to overpower the uplink frequency of a broadcast relay station, breaking into the transmitter area and splicing audio directly into the feed, and cyberattacks on internet-connected broadcasting equipment.

As a cable television operator connects itself in the signal path between individual stations and the system's subscribers, broadcasters have fallen victim to signal tampering on cable systems on multiple occasions. During late-night broadcasting in the Graveyard slot, some channels will interrupt retro programs with infomercials, or begin the broadcast at an odd time, such as 10:37 as opposed to 10:30 depending on their schedule arrangements. This serves as a means for audience retention by the channel.