| Official Name: | Wan Yai |
| Native Name: | หว้านใหญ่ |
| Native Name Lang: | th |
| Settlement Type: | District |
| Subdivision Type: | Country |
| Subdivision Name: |  Thailand |
| Subdivision Type1: | Province |
| Subdivision Name1: | Mukdahan |
| Subdivision Type2: | Seat |
| Subdivision Name2: | Wan Yai |
| Subdivision Type3: | Tambon |
| Subdivision Type4: | Muban |
| Established Title: | District established |
| Population Total: | 18683 |
| Population As Of: | 2005 |
| Blank Name Sec1: | Postal code |
| Blank Info Sec1: | 49150 |
| Blank Name Sec2: | Geocode |
| Blank Info Sec2: | 4906 |
| Timezone: | ICT |
| Utc Offset: | +7 |
| Coordinates: | 16.7275°N 104.7389°W |
Wan Yai (Thai: หว้านใหญ่, in Thai pronounced as /wâːn jàj/; หว้านใหญ่, in Lao pronounced as /wàːn ɲāj/) is a district (amphoe) of Mukdahan province, northeastern Thailand.
Neighboring districts are (from the south clockwise) Mueang Mukdahan of Mukdahan Province and That Phanom of Nakhon Phanom province. To the east across the Mekong River is the Laotian province of Savannakhet.
The important water resource is the Mekong.
The minor district (king amphoe) Wan Yai was created on 16 September 1977, when the tambon Wan Yai, Pong Kham, and Bang Sai Noi were split off from Mukdahan district.[1] In 1982 it was one of six districts which formed the new province of Mukdahan. The minor district was upgraded to a full district on 9 May 1992.[2]
The district is divided into five sub-districts (tambon), which are further subdivided into 44 villages (muban). There are no municipal (thesaban) areas, and four tambon administrative organization (TAO).
| No. | Name | Thai name | Villages | Pop. | ||
|---|---|---|---|---|---|---|
| 1. | Wan Yai | หว้านใหญ่ | 11 | 4,739 | ||
| 2. | Pong Kham | ป่งขาม | 11 | 5,337 | ||
| 3. | Bang Sai Noi | บางทรายน้อย | 11 | 4,715 | ||
| 4. | Chanot | ชะโนด | 5 | 2,444 | ||
| 5. | Dong Mu | ดงหมู | 6 | 1,448 |