Mary Margaret Nelis, is an Irish former politician who was a Sinn Féin Member of the Northern Ireland Assembly (MLA) for Foyle from 1998 to 2004.

She trained as an adult literacy teacher and was a founding member of the Derry Reading Workshop, an organisation set up to help those with educational needs In 1974, she joined the Social Democratic and Labour Party (SDLP), but resigned a year later.

She was the centre of some controversy in 1978 when Conor Cruise O'Brien, editor-in-chief of The Observer, refused to publish an article about her by Mary Holland, describing Nelis as a "conwoman".

She was re-elected in 2003, but resigned a year later to care for her husband, who sustained injuries in a road traffic accident; and was succeeded by Raymond McCartney.

She writes the political column in the Sunday Journal and also contributes to the Sinn Féin paper, An Phoblacht.