Lally Horstmann (née Léonie Lizzie Fanny Helene von Schwabach; 17 March 1898 – 10 August 1954) was a German writer and salonnière.

She authored two memoirs, Kein Grund für Tränen and Unendlich viel ist uns geblieben, which documented her life in Nazi Germany during World War II.

Horstmann grew up in the cosmopolitan, cultivated milieu of the Jewish financial bourgeoisie in Berlin and on the Schwabach family's country estate in Kerzendorf, near Ludwigsfelde.

In 1907, her father was raised to the hereditary Prussian nobility by Emperor Wilhelm II, at which point the family surname took on the nobiliary particle von (descending from).

[4] She authored a variety of historical and non-fiction works, including Kein Grund für Tränen and Unendlich viel ist uns geblieben, which documented life during the war.