A cross-flow turbine, Bánki-Michell turbine, or Ossberger turbine is a water turbine developed by the Australian Anthony Michell, the Hungarian Donát Bánki and the German Fritz Ossberger. Michell obtained patents for his turbine design in 1903, and the manufacturing company Weymouth made it for many years. Ossberger's first patent was granted in 1933, and he manufactured this turbine as a standard product. Today, the company founded by Ossberger which bears his name is the leading manufacturer of this type of turbine.

A water turbine is a rotary machine that converts kinetic energy and potential energy of water into mechanical work.