Karoline Jagemann (from 1809 Freifrau) von Heygendorff (25 January 1777, in Weimar – 10 July 1848, in Dresden) was a major German tragedienne and singer. Her great roles included Elizabeth in Mary Stuart (1800) and Beatrice in The Bride of Messina (1803). She is also notable as a mistress of Karl August, Grand Duke of Saxe-Weimar-Eisenach, the father of her three children. Both she and Karl August had their portraits painted by Heinrich Christoph Kolbe.
Henriette Karoline Friedericke Jagemann was the daughter of the scholar and librarian Christian Joseph Jagemann (1735–1804), and sister of the painter Ferdinand Jagemann (1780–1820). She studied first at the Weimar Princely Free Zeichenschule, where her brother was later a lecturer. From 1790 she trained in acting and singing in Mannheim under August Iffland and Heinrich Beck.
She made her debut in 1792 in the title role of the opera Oberon – The Fairy King by Paul Wranitzky at Mannheim's Nationaltheater and was engaged as a court-singer in Weimar in 1797. She and the soprano Henriette Eberwein (1790 - 1849), the tenor Carl Melchior Jakob Moltke, and the bass Karl Stromeier collectively made up the "Weimar Quartet". She was guest-singer in 1798 at Berlin, in 1800 at Vienna, and later in Stuttgart, Frankfurt am Main and Leipzig.