The wars of Alexander the Great were a series of conquests that were carried out by Alexander III of Macedon from 336 BC to 323 BC. They began with battles against the Achaemenid Persian Empire, then under the rule of Darius III of Persia. After Alexander's chain of victories against Achaemenid Persia, he began a campaign against local chieftains and warlords that stretched from Greece to as far as the region of Punjab in South Asia. At the time of his death, he ruled over most regions of Greece and the conquered Achaemenid Empire ; he did not, however, manage to conquer the Indian subcontinent in its entirety according to his initial plan. Despite his military accomplishments, Alexander did not provide any stable alternative to the rule of the Achaemenid Empire, and his untimely death threw the vast territories he conquered into a series of civil wars, commonly known as the Wars of the Diadochi.

Alexander III of Macedon, most commonly known as Alexander the Great, was a king of the ancient Greek kingdom of Macedon. He succeeded his father Philip II to the throne in 336 BC at the age of 20 and spent most of his ruling years conducting a lengthy military campaign throughout Western Asia, Central Asia, parts of South Asia, and Egypt. By the age of 30, he had created one of the largest empires in history, stretching from Greece to northwestern India. He was undefeated in battle and is widely considered to be one of history's greatest and most successful military commanders.