Morgenthau is a German surname meaning "morning dew". Notable people with the surname include:

• Elinor Morgenthau (1891–1949), American Democratic party activist
• Hans Morgenthau (1904–1980), German-American international relations theorist
• Henry Morgenthau Sr. (1856–1946), American diplomat and businessman
• Henry Morgenthau Jr. (1891–1967), United States Secretary of the Treasury and proponent of the Morgenthau Plan
• Henry Morgenthau III (1917–2018) American author and television producer
• Kramer Morgenthau (1966–) American cinematographer
• Robert M. Morgenthau (1919–2019), American lawyer

Some fictional characters with this surname are:

• Karl Morgenthau
• Karli Morgenthau

• Morgenthau Lectures, named after Hans Morgenthau
• Ambassador Morgenthau's Story (1918), published memoirs of Henry Morgenthau Sr.
• Morgenthau Report, a report issued by the United States' commission led by Henry Morgenthau Sr.
• USCGC Morgenthau (WHEC-722), a U.S. Coast Guard cutter
• Morgenthau Plan, a plan for the occupation of Germany after World War II.
• Morgenthau Family Tree" (PDF). Museum of Jewish Heritage. Retrieved 2015-07-16.
• Kestenbaum, Lawrence. "The Political Graveyard: Morgenthau-Lehman family of New York". The Political Graveyard. Retrieved 2015-07-16.
• Morgenthau, Henry. Mostly Morgenthaus: A Family History. New York, NY: Ticknor & Fields. ISBN 9780899199764