Udaypur Wildlife Sanctuary (also spelled Udaipur) is a wildlife sanctuary located in West Champaran district of Bihar state, India. It was established in 1978, and covers an area of 8.74 km².
The wildlife sanctuary is predominantly wetland, located on an oxbow lake in the floodplain of the Gandaki River. It is home to a variety of water birds, both resident and migratory. The sanctuary has areas of swamp forest, dry riverine forest, and khair-sissoo forest (Acacia catechu-Dalbergia sissoo). It is in the Lower Gangetic Plains moist deciduous forests ecoregion.
The sanctuary has a rest house. The nearest town and railhead is Bettiah. The sanctuary is under the authority of the Deputy Director of the Champaran Forest Division, headquartered in Bettiah.