The Sulu Sea is a body of water in the southwestern area of the Philippines, separated from the South China Sea in the northwest by Palawan and from the Celebes Sea in the southeast by the Sulu Archipelago. Borneo is found to the southwest and Visayas to the northeast.

Sulu Sea contains a number of islands. The Cuyo Islands and Cagayan Sulu are part of the province of Palawan while Mapun and the Turtle Islands are part of the province of Tawi-Tawi. Sulu Sea is also where the Tubbataha Reef National Marine Park, one of the World Heritage Sites is located.

The International Hydrographic Organization (IHO) defines the Sulu Sea as being one of the waters of the East Indian Archipelago. The IHO defines its limits as follows:

On the Northwest. From Tanjong Sampanmangio, the North point of Borneo, along the Eastern limit of South China Sea to Cape Calavite, the Northwest point of Mindoro.

On the Northeast. The Southwest coast of Mindoro to Buruncan Point, its Southern extreme, thence a line through Semirara and Kaluya Islands to Nasog Point (11°53′N 121°53′E / 11.883°N 121.883°E / 11.883; 121.883) the Northwestern extreme of Panay, along the West and Southeast coast of that island to Tagubanhan Island (11°08′N 123°07′E / 11.133°N 123.117°E / 11.133; 123.117), thence a line to the Northern extreme of Negros and down the West coast to Siaton Point, its Southern extreme, thence across to Tagolo Point (8°44′N 123°22′E / 8.733°N 123.367°E / 8.733; 123.367), Mindanao.

Sulu (Tausūg: سوگ, Sūg) is an autonomous island province of the Philippines located in the Autonomous Region in Muslim Mindanao (ARMM). Its capital is Jolo and occupies the middle group of islands of the Sulu Archipelago, between Basilan and Tawi-Tawi. It is home to the historical Sultanate of Sulu.

The peaceful advent of Islam around 1138 through merchants and traders had a distinct influence on Southeast Asia. The coming of Arabs, Persians and other Muslims paved the way for the arrival of religious missionaries, traders, scholars and travelers to Sulu and Mindanao in the 12th century.

A landmark born of the social process was the founding of the principality of Buansa Sumatra, who settled there and married the daughter. A decade earlier (1380), Karim-ul-Mahkdum, an Arab religious missionary and learned judge, reinforced the Islamic foundation of Rajah Baguinda’s polity (1390–1460) and that of the Sultanate of Sayid Abubakar, princely scholar from Arabia who married Paramisuli, the daughter of Rajah Baguinda. Sayid Abubakar eventually inherited the rule of Rajah Baguinda, established the Sultanate and became the first Sultan of Sulu. To consolidate his rule, Sayid Abubakar united the local political units under the umbrella of the Sultanate. He brought Sulu, Zamboanga Peninsula, Palawan and Basilan under its aegis.