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. He later took classes in botany, zoology and foreign languages at the University of Berlin. Beginning in 1852 he was associated with the Gärtner-Lehr-Anstalt zu Erfurt (a gardener-teaching institution in Erfurt) as an instructor and inspector.