Jan Marijnissen, Dutch journalist and politician
Johannes Guillaume Christianus Andreas "Jan" Marijnissen (Jan Marijnissen ) (born 8 October 1952) is a retired Dutch politician of the Socialist Party (SP).

Marijnissen, a welder by occupation, was selected as Leader of the Socialist Party after the death of Daan Monjé on 1 October 1986 and became Chairman of the Socialist Party on 20 May 1988. For the election of 1994 Marijnissen was the Lijsttrekker (top candidate) and won two seats in the House of Representatives, the first time the Socialist Party won representation in the States General of the Netherlands. Marijnissen was elected as a Member of the House of Representatives on 17 May 1994 and became the Parliamentary leader of the Socialist Party in the House of Representatives. For the elections of 1998 and 2002 Marijnissen again as Lijsttrekker won three and four seats respectively. For the election of 2006 Marijnissen for the fifth time as Lijsttrekker won sixteen seats and the Socialist Party became the third-largest party in the House of Representatives. On 20 June 2008 Marijnissen announced his retirement as Leader of the Socialist Party and Parliamentary leader of the Socialist Party in the House of Representatives citing health reasons. Marijnissen remained a Member of the House of Representatives until after the 2010 general election. Marijnissen stood down as Chairman of the Socialist Party on 28 November 2015.

He is the father of Lilian Marijnissen, the current Leader of the Socialist Party.