Marjorie (Mo) Mowlam (born September 18 1949) is a British politician and served as a Labour MP.

She was born in Watford but grew up in Coventry, attending the Coundon Court Comprehensive school, and then studied at the Universities of Durham and Iowa. She became the MP for Redcar in 1987, becoming opposition spokesperson on Northern Ireland in that year. Since then she held a variety of posts, and became Shadow Secretary of State for Northern Ireland in 1994.

After the 1997 General Election she was made Secretary of State for Northern Ireland, and was succesful in helping to restore an IRA ceasefire, and including Sinn Fein in the multi-party talks, and paid a visit to loyalist prisoners in the Maze prison in an attempt to get the loyalists to sign up to what became the Good Friday Agreement.

She was replaced as Northern Ireland Secretary in 1999 by Peter Mandelson, and demoted to Cabinet Office Minister, and soon afterwards announced her intention to retire from Parliament, and relinquished her seat at the 2001 election.

She has been a noted critic of the government, especially on the topic of policy towards Iraq.