Langkawi scored 92.99 points out of 100, according to the magazine's annual Readers' Choice Awards.
Located about 30 km off northwestern Malaysia, Langkawi is an archipelago of 99 islands and famous for being a duty-free destination as most necessities on the island are tax-free.
The island has a tropical monsoon climate with a short dry season from December to February and a long rainy season from March to November.
Last year, Phu Quoc was voted the second most beautiful island in Asia.
This year, Langkawi is followed by Thailand's Koh Samui, Boracay and Palawan of the Philippines. The region's popular tourist island Bali comes in 6th.
More than 757,000 Condé Nast Traveler readers participated in the survey, sharing their opinions on various travel experiences, including cities, islands, hotels, resorts, cruise ships, spas, and airlines.
The Readers' Choice Awards, the longest-running accolade in the travel industry, celebrate excellence in hotels, resorts, and destinations around the world.