| Official Name: | Khao Saming |
| Native Name: | เขาสมิง |
| Native Name Lang: | th |
| Settlement Type: | District |
| Subdivision Type: | Country |
| Subdivision Name: | Thailand |
| Subdivision Type1: | Province |
| Subdivision Name1: | Trat |
| Subdivision Type2: | Seat |
| Subdivision Type3: | Tambon |
| Subdivision Type4: | Muban |
| Established Title: | District established |
| Population Total: | 40499 |
| Population As Of: | 2000 |
| Blank Name Sec1: | Postal code |
| Blank Info Sec1: | 23130 |
| Blank Name Sec2: | Geocode |
| Blank Info Sec2: | 2303 |
| Timezone: | ICT |
| Utc Offset: | +7 |
| Coordinates: | 12.3533°N 102.435°W |
Khao Saming (in Thai pronounced as /kʰǎw sā.mǐŋ/) is a district (amphoe) in Trat province, eastern Thailand.
The district was established in 1898, but its name and the location of the district office had changed several times in its history. At first named Si Bua Thong, then Thung Yai, it was finally renamed Khao Saming when the district office was moved to Ban Tha Kathon in Tambon Khao Saming. The present district office building was opened on 14 February 2000.
Neighboring districts are (from the north clockwise) Khlung of Chanthaburi province, Bo Rai, Mueang Trat, Laem Ngop of Trat Province.
The district is divided into eight sub-districts (tambons), which are further subdivided into 66 villages (mubans). Two townships (thesaban tambon) are in the district: Saen Tung covers parts of the tambon Saen Tung, and Khao Saming covers parts of the tambon Khao Saming and Thung Nonsi. There are a further eight tambon administrative organizations (TAO).
| 1. | Khao Saming | เขาสมิง | ||
| 2. | Saen Tung | แสนตุ้ง | ||
| 3. | Wang Takhian | วังตะเคียน | ||
| 4. | Tha Som | ท่าโสม | ||
| 5. | Sato | สะตอ | ||
| 6. | Pranit | ประณีต | ||
| 7. | Thep Nimit | เทพนิมิต | ||
| 8. | Thung Nonsi | ทุ่งนนทรี |