Karl Theodor Rümpler (1817 in Alterstedt – 23 May 1891 in Erfurt) was a German botanist and horticulturist.
He developed a passion for botany in his youth, and studied natural sciences at the gymnasium in Mühlhausen, where one of his classmates was Wilhelm Gerhard Walpers.
From 1873 onward, he was director of the newly established agricultural school in Erfurt.
[2] He is remembered for his investigations of the family Cactaceae, and was the taxonomic authority of numerous cactus species.
[3] In 1886, he published a new edition of Karl Friedrich Förster's 1846 "Handbuch der Cacteenkunde in ihrem ganzen Umfange".