Caesar, originally a cognomen in ancient Rome, may mean:

• Julius Caesar (100 BC–44 BC), the most famous individual with the name.
• Augustus Caesar, his adopted son and first Roman Emperor.
• The Caesar cipher used by Julius Caesar in his military campaigns.
• Caesar, a title used by Roman Emperors.
• Caesar, duc de Choiseul (1602–1675), a French marshal and diplomatist.
• Caesar cocktail, a cocktail made with vodka and Clamato that is popular primarily in Canada.
• Caesar Cardini (1896–1956), an Italian hotel owner, restaurateur, and chef in Tijuana, Mexico.
• Caesar salad, a recipe for salad invented by Caesar Cardini.
• "Caesar", a popular haircut, in which the hair is cut extra low and evenly on all sides.
• Caesar , the operator of a popular technology website, Ars Technica.
• Caesar, a series of computer games.
• The Center of Advanced European Studies and Research , an international research center in Bonn, Germany.
• HMS Caesar, four ships of the Royal Navy.

See also Kaiser and Tsar, which are variant spellings of the name.