Leonnatus (356 BC - 322 BC), Macedonian officer of Alexander the Great and one of the diadochi.

He was member of the royal house of Lyncestis , a small kingdom that had been included in Macedonia by king Philip II of Macedon. Leonnatus was the same age as Alexander and has been very close to the Alexander. Later, he was one of Alexander's seven bodyguards. After the Alexander died in 323 BC, new regent Perdiccas made Leonnatus satrap of Hellespontine Phrygia.

Alexander's sister Cleopatra, the widow of king Alexander I of Epirus, offered her hand to Leonnatus. In the meantime, when the Athenians heard that Alexander had died, they revolted against Macedons and regent Antipater. Leonnatus led an army of 20,000 infantry with 1500 cavalry to releive Antipater from siege in Lamia (see Lamian War). He intervened probable in ambitions to usurp Antipater's power. A victory in battle against the Greeks would certainly enhance his claim to the throne. Leonnatus was killed in battle against Athenians and the marriage with Cleopatra never took place.