Ian Deans (born August 16, 1937) is a former Canadian politician.

Born in Scotland, Deans moved to Canada as a youth and found work as a firefighter. He was first elected to the Ontario legislature as an Ontario New Democratic Party MPP in the 1967 provincial election representing the Hamilton-area riding of Wentworth. In 1978 he ran in the Ontario NDP leadership convention to succeed Stephen Lewis but lost by less than 200 votes to Michael Cassidy. Deans resigned from the legislature the next year and won a seat in the Canadian House of Commons during the 1980 Canadian election representing Hamilton Mountain.

Deans served as acting House Leader for the NDP during the illness of Stanley Knowles and became official House Leader following the 1984 Canadian election.

In the fall of 1986 he surprised colleagues by accepting a six figure salary job from Progressive Conservative Prime Minister Brian Mulroney as an administrator in the public service.

His wife, Diane Deans, is an Ottawa city councillor and ran for the Liberal Party nomination for the 2004 Canadian election in the riding of Ottawa South losing to David McGuinty.