Carl Eduard Cramer (4 March 1831 – 24 November 1901) was a Swiss botanist who was born in Zurich.
He studied at Zurich and Freiburg, where he received his doctorate in 1855. As a young man his mentor was the famed botanist Karl Wilhelm von Nägeli (1817–1891). He became a lecturer (1857) and later a professor of botany (1861–1901) at the Eidgenössische Technische Hochschule (Federal Polytechnic School) in Zurich. He also taught at the University of Zurich (1880–1883) and was director of its botanical garden from 1882 until 1893.
Cramer's specialty dealt with the physiology, genealogy and growth of plant cells. He was the author of several botanical works, including Pflanzen physiologische Untersuchungen (1855–1857), which he co-wrote with Karl von Nägeli. Cramer also did extensive work in the fields of bacteriology, vegetable teratology, cryptogamic flora and mycology (especially mushrooms).