Katja Hoyer (born 1985) is a German-British historian, journalist and writer.

Hoyer was born in Wilhelm-Pieck-Stadt Guben, Bezirk Cottbus, German Democratic Republic (GDR), where her mother was a teacher and her father an officer of the National People's Army. She received a Master's degree from the University of Jena and moved to the United Kingdom in about 2010.

Hoyer is a visiting research fellow at King's College London and has published three books about the history of Germany. She is also a journalist for The Spectator, The Washington Post, Times Literary Supplement, UnHerd, and Die Welt.

Hoyer is a Fellow of the Royal Historical Society.