Marius Job Cohen[a] (born 18 October 1947) is a retired Dutch politician and jurist who served as Mayor of Amsterdam from 2001 to 2010 and Leader of the Labour Party (PvdA) from 2010 to 2012.

Cohen also returned to State University of Limburg and again worked as professor of Jurisprudence and served as Rector Magnificus from January 1995 until August 1998.

Following the resignation of Parliamentary leader Joop van den Berg [nl] Cohen was selected as his successor on 1 August 1996.

After the election of 1998 Cohen was appointed as State Secretary for Justice in the Cabinet Kok II taking office on 3 August 1998.

[4][5] Cohen retired from active politics at 64 and became active in the public sector as a non-profit director and served on several state commissions [nl] and councils on behalf of the government, and worked as a distinguished professor of Constitutional law and Governmental studies at his alma mater in Leiden from April 2014 until January 2019.

[17] On 1 September 1981, he joined the State University of Limburg in a higher scientific capacity, and was chairman of the commission that prepared the establishment of a faculty of law.

On 1 September 1983, Cohen became professor of methods and techniques at the faculty of law; on 1 January 1991 he also became rector magnificus of the State University of Limburg.

On 3 August 1998, he resigned from the Senate to take up the position of State Secretary for Justice in the second cabinet of Wim Kok, dealing chiefly with immigration.

[21] On 2 February 2002, Job Cohen performed the civil marriage of Prince Willem-Alexander and Máxima Zorreguieta in the Beurs van Berlage in Amsterdam.

Time awarded Cohen the title "European Hero" in 2005, for his inclusive approach towards the Muslim community after the murder, defusing tension in the city.

[23] Cohen found himself thrown into the role of mediator between the city's Muslims, the original Dutch population and other groups in the cultural and racial mix.

[24] By his visiting ethnic groups, organizing debates among religious leaders and his listening and promoting dialogue, he received from opponents the mocking nickname of "tea drinker" – an image that would be exploited by them when he returned in the Dutch national politics in 2010.

Cohen's politics towards ethnic minorities in Amsterdam was characterized by the slogan "keeping things together" (de boel bij elkaar houden).

On 2 May 2006, Immigration Minister Rita Verdonk of the centre-right VVD accused Amsterdam of becoming a "banana republic" with a lax safety policy; she cited the criminal liquidations and the disturbance caused by young people as examples of this.

World Mayor praised Cohen's leadership following the murder of Theo van Gogh in 2004, and his efforts at bringing together the diverse population of Amsterdam.

The city council bought 18 buildings in the red light district De Wallen from Charlie Geerts in order to convert them into upscale establishments and revoked the license of the luxury brothel Yab Yum.

In his retirement, he served as chair of the supervisory board of NVVE, a Dutch right to die association, and he has been a guest speaker about World War II at schools.