Heinlein or Henlein is a German surname. Notable people with the surname include:
* Karl Heinlein (1892–1960), Austrian former footballer
* Klaus Heinlein (born 1953), German former footballer
* Konrad Henlein (1898–1945), Nazi German politician
* Martina Heinlein, a field hockey player in the 2008 Summer Olympics
* Max Hussarek von Heinlein (1865–1935), Austrian politician, Prime Minister of Austria in 1918
* Peter Henlein (1479/80–1542), German locksmith and watchmaker, often considered the inventor of the portable timepiece
* Robert A. Heinlein (1907–1988), American science fiction writer
** Virginia Heinlein (1916–2003), third wife of Robert A. Heinlein
{{surname, Henlein
German-language surnames
Surnames from given names
de:Henlein