Sisse Marie Welling is a Danish politician from the Socialist People’s Party (SF) and has served as Lord Mayor of Copenhagen Municipality since 1 January 2026. She is the first non-Social Democrat to hold the position in more than 100 years, following a broad coalition agreement formed after the 2025 municipal election.

Her key political priorities are:

• Housing policy, including building more affordable and sustainable housing in Copenhagen
• Sustainable urban development, including more green urban spaces, more harbor baths, and sustainable infrastructure such as cycling and the metro
• The well-being of children and young people, including creating good everyday conditions for families with children and ensuring high-quality public institutions and schools

She was elected to the Copenhagen City Council (Borgerrepræsentationen) in 2010 at the age of 23 and has been an active figure in Copenhagen’s local politics for more than 15 years. For seven years from 1 January 2018 until the end of 2025, she served as Mayor of Health and Care.

As vice-chair of the C40 Steering Committee, the Lord Mayor will be a strong voice for sustainable urban development with a focus on sustainable and affordable housing and urban nature – all aimed at supporting and fostering a liveable, affordable, and healthy city. A city that thrives with green spaces, harbour baths, and strong everyday conditions for residents, not at least children. In Copenhagen, climate action is integrated across sectors – from how people move around the city and how homes are heated, to how neighbourhoods are planned and how the city adapts to changing weather.

She became politically active at the age of 14 when she joined SF Youth and she has earned a master’s degree in history from the University of Copenhagen.