The 39-year-old actress, who spent seven seasons on the show before quitting last year, will host on May 11, reported E! online.
Wiig, hailed by showrunner Lorne Michaels as one of the top three or four cast members of all time, recently said she has felt lost since quitting 'SNL'.
"The show was seven years of my life and a six-day work week and you're constantly with your friends all day, all night. You sort of live and breathe the show. Then, when it's over, you kind of feel a little lost ... It was definitely an adjustment - even just the hours and no longer being in New York," she said.
Meanwhile, Zach Galifianakis will host the May 4 'SNL' episode, while NBC has announced Ben Affleck will take charge for the season finale on May 18, with musical guest Kanye West.