Joachim Wendler (born June 6, 1939, Erfurt, Germany – died September 25, 1975, Rockport, Massachusetts) was a West German aquanaut who died of an air embolism while returning to the surface of the Gulf of Maine from the Helgoland underwater habitat. He was participating in a checkout mission for the First International Saturation Study of Herring and Hydroacoustics (FISSHH) project.