Marduk (Cuneiform: 𒀭𒀫𒌓 ^dAMAR.UTU; Sumerian: amar utu.k "calf of the sun; solar calf"; Hebrew: מְרֹדַךְ‎, Modern: Mərōdaḵ, Tiberian: Merōḏaḵ) was a god from ancient Mesopotamia and patron deity of the city of Babylon. When Babylon became the political center of the Euphrates valley in the time of Hammurabi (18th century BC), Marduk slowly started to rise to the position of the head of the Babylonian pantheon, a position he fully acquired by the second half of the second millennium BC. In the city of Babylon, Marduk was worshipped in the temple Esagila. Marduk is associated with the divine weapon Imhullu. His symbolic animal and servant, whom Marduk once vanquished, is the dragon Mušḫuššu. "Marduk" is the Babylonian form of his name.

The name Marduk was pronounced Marutuk. The etymology of the name Marduk is conjectured as derived from amar-Utu ("immortal son of Utu" or "bull calf of the sun god Utu"). The origin of Marduk's name may reflect an earlier genealogy, or have had cultural ties to the ancient city of Sippar (whose god was Utu), dating to the third millennium BC.

By the Hammurabi period, Marduk had become astrologically associated with the planet Jupiter.