Marg Downey (born 1961 in Melbourne) is an Australian comedian.
Downey first rose to prominence in the sketch comedy program The D-Generation on the Australian Broadcasting Corporation in the late 1980s. She subsequently appeared in later sketch comedy series with other members of The D-Generation, including Fast Forward, Full Frontal and Something Stupid. In these, she was known for her portrayals of a news anchor, a stern SBS presenter and for her spot-on impression of current affairs host Jana Wendt. Her spoof of "The What's On SBS Presenter" satirised the eccentricity of SBS programming, displaying grim masochistic determination to "not miss a moment of this scintillating entertainment".
In 2005, Downey was cast as a regular player in Seven's live comedy sketch show Let Loose Live, but the show was cancelled after just two episodes due to low ratings. The following year, she appeared in the sketch show Magda's Funny Bits alongside Magda Szubanski. In this show, she recreated her role as infomercial host Janelle, first developed on Fast Forward.