Katja Dörner (born 18 February 1976) is a German politician of the Alliance 90/The Greens who has been serving as mayor of Bonn since 2020.

From 2001 until 2003, Dörner worked as a legislative adviser to Sylvia Löhrmann, then the chairwoman of the Green Party's parliamentary group in the Landtag of North Rhine-Westphalia.

In parliament, she served on the Committee on Family Affairs, Senior Citizens, Women, and Youth.

From 2013 until 2020, Dörner served as vice-chair of the Green Party's parliamentary group, under the leadership of Katrin Göring-Eckardt and Anton Hofreiter.

[4] In the negotiations to form a coalition government under the leadership of Minister-President of North Rhine-Westphalia Hendrik Wüst following the 2022 state elections, Dörner was part of her party’s delegation.