The islands are a part of the state of Kedah, which is adjacent to the Thai border. On July 15, 2008, Sultan Abdul Halim of Kedah had consented to the change of name to Langkawi Permata Kedah in conjunction with his Golden Jubilee Celebration.

By far the largest of the islands is the eponymous Pulau Langkawi with a population of some 45,000, the only other inhabited island being nearby Pulau Tuba. Langkawi is also an administrative district with the town of Kuah as the capital and largest town. Langkawi is a duty-free island.

Langkawi lies north of the Strait of Malacca in the southern Andaman Sea near the border between Malaysia and Thailand. A few kilometres to the north lies the neighbouring Thai island of Ko Tarutao. The island group's main town, on the main island, is Kuah.

Langkawi's highest point is Gunung Raya, rising to 890 m above sea level in the main island's central-eastern area.

The archipelago consists of 99 islands with a total land area of 528 km2 (204 sq mi).