Marinduque (Filipino: Marinduke pronounced [mɑrinˈduke]) is an island province of the Philippines located in the MIMAROPA region in Luzon. Its capital is Boac. Marinduque lies between Tayabas Bay to the north and Sibuyan Sea to the south. It is located south and west of Quezon, east of Mindoro, and north of Romblon.

Legend has it that the island of Marinduque was formed as a consequence of a tragic love affair between two people: Mariin and Gatduke. Mariin's father, a local chieftain, did not approve of this affair and ordered the beheading of Gatduke. Before this could be done, the couple sailed out to sea and drowned themselves, forming the island now called Marinduque.

During the Spanish and early American occupations, Marinduque was part of Balayan Province (now Batangas) in the 16th century, Mindoro in the 17th century, and had a brief period as an independent province in 1901, when the Americans arrived.

During the Philippine-American War, Marinduque was the first island to have American concentration camps. Marinduque is the site of the Battle of Pulang Lupa, where 250 Filipino soldiers under Colonel Maximo Abad, defeated a smaller force of 54 American Infantrymen.