Christian Gottlieb Kratzenstein (30 January 1723, Wernigerode – 6 July 1795, Copenhagen) was a German-born medical doctor, physicist and engineer. From 1753 to the end of his life he was a professor at the University of Copenhagen where he served as rector four times. He is especially known for his investigations of the use of electricity in medicine and the first attempts at mechanical speech synthesis. As a teacher he wrote the first textbook on experimental physics in the united kingdom of Denmark-Norway.