The comedy is in development at 20th Century Fox TV, The Hollywood Reporter said Saturday.
It would be Gellar's second attempt at comedy on television; she shot a comedy pilot for HBO in 2009 that wasn't picked up.
The Fox sitcom, a name for which was not reported, was written by "Men at Work" staff writer Shepard Boucher. David Hemingson and Margaret Riley are attached as executive producers.
Gellar's most recent television work was CW's "Ringer," which was canceled at the end of last season. She's best known for starring in the supernatural drama "Buffy the Vampire Slayer."