Malay Peninsula (məlā´, mā´lā), southern extremity (c.70,000 sq mi/181,300 sq km) of the continent of Asia, lying between the Andaman Sea of the Indian Ocean and the Strait of Malacca on the west and the Gulf of Thailand and the South China Sea on the east. It stretches south for c.700 mi (1,100 km) from the Isthmus of Kra, where it is narrowest, to Singapore. The northern part of the peninsula forms a part of Thailand; the southern part constitutes West Malaysia, the Malayan part of Malaysia. The peninsula forms a physical and cultural link between the mainland of Asia and the islands of Indonesia (often included in the Malay Archipelago).
A mountain range (the highest point of which is Gunong Tahan, 7,186 ft/2,190 m, in Malaysia) forms the backbone of the peninsula; from it numerous short, swift rivers flow east and west. More than half of the land surface is covered with tropical rain forest; the only open areas, aside from clearings made for settlement and agriculture, are the alluvial plains of the west-central portion of the peninsula and stretches along the rivers. The region is one of the richest of the world in the production of tin and rubber; other products include timber, copra and coconut oil, palm oil, tapioca, peanuts, pineapples, and bananas. Rice is the chief foodstuff.
The Malays, historically the dominant cultural group, probably came originally from S China (c.2,000 BC), but marriages with other peoples have modified their ethnic characteristics. The Chinese are now nearly as numerous as the Malays; Indians and Thais form important minority groups. Small tribes of aborigines, descendants of pre-Malay immigrants, are found in the hills and jungles.
The Malay Peninsula was visited near the beginning of the Christian era by traders from India and in the succeeding centuries received, like Indonesia and Indochina, Buddhist and Brahman missionaries and Hindu colonists. Small Hinduized states sprang up, like Langkasuka in the area of modern Kedah. In the second half of the 8th cent. the peninsula fell under the domination of the Sailendra rulers of Sri Vijaya (from Sumatra), who adopted Mahayana Buddhism. Their cities in Kedah and Pattani rivaled the importance of their capital at Palembang.
The peninsula was overrun in the 11th cent. by the Cholas from the Coromandel Coast of India; after about 50 years, the Sailendras, somewhat weakened, resumed their sway. Sailendra rule ended in the late 13th cent., when Sumatra and some southern areas of the Malay Peninsula fell to a Javan invasion and when the Thai king of Sukhothai swept over the peninsula from the north. The Sumatran kingdom of Melayu next ruled over the south of the peninsula, to be followed in turn (late 14th cent.) by Madjapahit, which was the last Hindu empire of Java, and by the Thai king of Ayutthaya. The fall of Madjapahit opened the way for the primacy of a Malay state, Malacca (see Melaka). In the 15th cent., the Malays, beginning with the Malaccans, were converted to Islam (which remains the religion of most Malays).
The 16th cent. brought the first Europeans. The Portuguese seized Malacca (1511), and soon afterward Dutch traders appeared in Malayan waters. Malacca fell to the Dutch in 1641. The important British role on the peninsula began with the founding of settlements at Pinang (1786) and Singapore (1819). The coming of the Portuguese had plunged the peninsula into anarchy. The last sultan of Malacca, in flight from the Portuguese, founded a kingdom based on the Riau Archipelago and Johor, but the rulers of the petty states in the south gradually achieved independence, while the rising power of Siam and an increasingly imperial Britain became rivals. The British established protectorates over several Malay states, and in 1909 the boundary between Siam and Malaya was fixed by Siam's transfer to Great Britain of suzerainty over Kedah, Perlis, Kelantan, and Terengganu.
See Malaysia and Thailand for the later history of the peninsula.