Maria Johanna Theodora Martens (born 8 January 1955 in Doetinchem, Gelderland) is a Dutch politician. She is a member of the Christian Democratic Appeal. From 2011 until 2019 she was a member of the Dutch Senate.

From 1999 to 2009 she was a Member of the European Parliament (MEP). There she was a member of the bureau of the EPP-ED group in the European Parliament and sat on the European Parliament's Committee on Development.

She was also a substitute for the Subcommittee on Security and Defence and a member of the delegation to the ACP-EU Joint Parliamentary Assembly.

• Higher degree in theology (1984)
• NIMA (Netherlands Marketing Institute) A and B diplomas
• Lecturer in Life Philosophy (1984)
• Foreign Affairs Secretary, Netherlands Mission Council (1984–1988)
• Study secretary, VKMO (Association of Catholic Social Organisations) (1988–1999)
• Chairwoman, Nijmegen CDA
• Member of the party council
• Member of the editorial team of CD Verkenningen
• Chairwoman, European Forum of National Committees of the Laity (1996–2000)
• Chairwoman, Netherlands Episcopal Committee for the year 2000 (1996–2000)
• Member of the governing board of the Catholic Theological University, Utrecht (since 1998)
• Commissioner for recreation in the Veluwe area (RGV)
• Member of the executive board of the World Population Fund (WPF)
• Member of the European Parliament (since 1999)
• Awarded knighthood in the Order of Orange-Nassau (2009)
• Decorated in Order of St. Gregory the Great (2024).

• (in Dutch) Parlement.com biography

• Official website
• European Parliament biography^{[permanent dead link]}
• Declaration (PDF) of financial interests (in Dutch)
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v t e « 1999–2004 «  Dutch members of the European Parliament, 2004–2009   » 2009–2014 »
Christian Democratic Appeal	Bert Doorn Camiel Eurlings Esther de Lange Albert-Jan Maat Maria Martens Lambert van Nistelrooij Ria Oomen-Ruijten Joop Post Cornelis Visser Corien Wortmann-Kool
Labour Party	Max van den Berg Thijs Berman Emine Bozkurt Ieke van den Burg Jan Cremers Dorette Corbey Lily Jacobs Edith Mastenbroek Jan Marinus Wiersma
People's Party for Freedom and Democracy	Jeanine Hennis-Plasschaert Jules Maaten Toine Manders Jan Mulder
GroenLinks	Kathalijne Buitenweg Joost Lagendijk
Europe Transparent	Paul van Buitenen Els de Groen
Socialist Party	Kartika Liotard Erik Meijer
Christian Union – Reformed Political Party	Hans Blokland (Christian Union) Bas Belder (Reformed Political Party)
Democrats 66	Sophie in 't Veld
Independent (members who left their parties)	Els de Groen

v t e « 1994–1999 «  Dutch members of the European Parliament, 1999–2004   » 2004–2009 »
Christian Democratic Appeal	Albert Jan Maat Maria Martens Bert Doorn Hanja Maij-Weggen Wim van Velzen Bartho Pronk Arie Oostlander Karla Peijs Ria Oomen-Ruijten Peter Pex Cees Bremmer
Labour Party	Michiel van Hulten Joke Swiebel Ieke van den Burg Dorette Corbey Max van den Berg Jan Marinus Wiersma
People's Party for Freedom and Democracy	Jules Maaten Toine Manders Jan Mulder Elly Plooij-van Gorsel Marieke Sanders-ten Holte Jan-Kees Wiebenga Herman Vermeer
GroenLinks	Theo Bouwman Kathalijne Buitenweg Joost Lagendijk Alexander de Roo
SGP, GPV and RPF	Bas Belder (SGP) Hans Blokland (GPV) Rijk van Dam (RPF)
Democrats 66	Lousewies van der Laan Bob van den Bos Johanna Boogerd-Quaak
Socialist Party	Erik Meijer