"Only Daddy That'll Walk the Line" is a song written by Jimmy Bryant, and recorded by American country music singer and musician Waylon Jennings. It was released in July 1968 as the second single from Jennings' album Only the Greatest.

Billboard, in a review of the album, said that it and "Walk On Out of My Mind" were "typical of the robust, compelling vocal style." Nathan Brackett and Christian Hoard, in The New Rolling Stone Album Guide, wrote that Jennings began to "really assert his rough-hewn sensibility" on the song.

The song was featured in season seven episode five of Mad Men.

The song spent eighteen weeks on the Hot Country Singles charts, peaking at #2 and holding that peak for five weeks. In Canada, it reached Number One on the RPM Country Tracks charts for the week ending September 30, 1968.

Linda Ronstadt included a gender-reversed version of the song (sung as "The Only Mama That'll Walk the Line") on her 1969 album Hand Sown ... Home Grown; The song became a staple of Ronstadt's set lists at her concerts during the late 1960s and early '70s. She performed it on The Johnny Cash Show in June 1969, nearly a year before Jennings performed it on the same show.

Hank Williams Jr. included a version of the song on his album Family Tradition, which was released in 1979.

In 1991, The Kentucky Headhunters recorded a cover version for the album Electric Barnyard. Also released as a single that year, this version spent seven weeks on the same chart and peaked at #60.

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