Lilienthal is a German and Jewish surname. Notable people with the surname include:
- Alfred Lilienthal, American author
- Andor Lilienthal, Hungarian chess player
- David E. Lilienthal, (1899–1981) American public official at TVA and Atomic Energy Commission
- Gustav Lilienthal, German aviation pioneer, brother of Otto
- Max Lilienthal, Early Reform Rabbi
- Otto Lilienthal, German aviation pioneer, brother of Gustav
- Peter Lilienthal, film director
- Philip H. Lilienthal, American lawyer, camp director, and philanthropist
- Philip N. Lilienthal (1850–1908). American banker