Deep Throat is a fictional character in the television show The X-Files, played by Jerry Hardin. The character is named after W. Mark Felt, otherwise known as Deep Throat of the Watergate scandal. In the Season 4 episode, Musings of a Cigarette Smoking Man, it is suggested that Deep Throat's real name may be Ronald.

Deep Throat first appears in the episode "Deep Throat", warning agent Fox Mulder of the danger he is in, and later offers to help him. He subsequently becomes Mulder's covert information source. Whenever Mulder needs Deep Throat's help, Mulder places a black light lamp in his window. This is similar to how Bob Woodward would "call" the real-life Deep Throat, in which he claimed to move a potted plant on his balcony a certain way to signal a meeting.