Kiss's drummer Peter Criss sings the song, which he co-wrote with Stan Penridge. The song was written before Criss had joined Kiss, while he was still a member of Chelsea. Criss came up with the melody for the song while on a train to New York City from New Jersey where the band practiced. He and Chelsea guitarist Stan Penridge wrote the song together.

Neither of the two women who inspired the song were actually named Beth. A bootleg exists of the song from 1971, but the song was sung "Beck, what can I do?" "Beck" was the nickname of fellow Chelsea member Mike Brand's wife, Becky, who would call often during practices to ask Mike when he was coming home. Years later, while in Kiss, both Bob Ezrin and Gene Simmons are credited for changing the song's title to "Beth," presumably to be more recognizable as a female name.

The song was a last-minute addition to the Destroyer album. According to Bill Aucoin, the manager of Kiss at that time, Gene Simmons and Paul Stanley did not want "Beth" on the album because it was not a typical Kiss song. Bill insisted on keeping the song on the record

When released as a single, however, "Beth" was initially the B-side of "Detroit Rock City". Some of the initial credit for the flip-hit goes to Rosalie Trombley, who was at the time the music director at "The Big 8" CKLW in Windsor, Ontario. The story goes that Rosalie's daughter had a copy of the 45 and was hooked on "Beth", and began nagging her mother about it. "Beth" wasn't being promoted as the "A" side, but Rosalie knew a hit when she heard one, and added it to CKLW's playlist. The rest is history, and after "Beth" became a smash, the members of KISS presented Rosalie's daughter with a gold record.  Kiss and Casablanca Records reissued "Beth" as an A-side with "Detroit Rock City" as the B-side, and it was far more successful.  The single went Gold in the United States (the first Kiss single to do so) on January 5, 1977.

In 1977, Kiss received a People's Choice Award for "Beth", one of the few industry awards the band ever won. [SOURCE]