Thung Yai-Huai Kha Khaeng Wildlife Sanctuary World Heritage property lies in Uthai Thani, Tak, and Kanchanaburi provinces in the west of Thailand, alongside the border with Myanmar. The property combines two contiguous sanctuaries, Thung Yai Naresuan and Huai Kha Khang, separately established as sanctuaries in 1972 and 1974, respectively. Thung Yai-Huai Kha Khaeng Wildlife Sanctuary encompasses two important river systems, the Upper Khwae Yai and the Huai Khakhaeng. The property, encompassing 622,200 hectares, is the largest conservation area in Mainland Southeast Asia and is one of Thailand’s least accessible and least disturbed forest areas.

The flora and fauna of the sanctuaries include associations found nowhere else, with many species of exclusively Sino-Himalayan, Sundaic, Indo-Burmese, and Indo-Chinese affinities, intermingling within the property. Many of these are rare, endangered, or endemic. The sanctuary’s importance as a conservation area lies in the heterogeneity and integrity of its habitats, the diversity of its flora and fauna, and the complexity of its ecosystem. The property contains exceptional natural beauty and aesthetic importance with steep sided valleys and impressive mountain peaks interspersed with small lowland plains. The scenic beauty of the property is exceptional, enhanced by the sight of a host of tributary streams and waterfalls, the unique mosaic of forest types and the sweeping spectacles of variations of colour, form, and foliage.

Thungyai–Huai Kha Khaeng Wildlife Sanctuaries  is the inscribed name of a UNESCO World Heritage Site in Thailand.