Petra Haden Sings: The Who Sell Out is an album by Petra Haden, an entirely a cappella interpretation of the album The Who Sell Out by English rock band The Who.

Haden supplies all of the vocals. It was released in 2005 on Bar None Records. The recording was inspired by former Minutemen bassist Mike Watt, who gave Haden the 8-track recorder with the original Who album on it.

The Who's guitarist and principal songwriter, Pete Townshend, had this to say about Haden's version of the album: "I was a little embarrassed to realize I was enjoying my own music so much, for in a way it was like hearing it for the first time.

What Petra does with her voice, which is not so easy to do, is challenge the entire rock framework ...

When she does depart from the original music she does it purely to bring a little piece of herself -- and when she appears she is so very welcome.

I felt like I'd received something better than a Grammy."