| Official Name: | Khao Chamao |
| Native Name: | เขาชะเมา |
| Native Name Lang: | th |
| Settlement Type: | District |
| Subdivision Type: | Country |
| Subdivision Name: | Thailand |
| Subdivision Type1: | Province |
| Subdivision Name1: | Rayong |
| Subdivision Type2: | Seat |
| Subdivision Name2: | Huai Thap Mon |
| Subdivision Type3: | Tambon |
| Subdivision Type4: | Muban |
| Established Title: | District established |
| Population Total: | 22432 |
| Population As Of: | 2005 |
| Blank Name Sec1: | Postal code |
| Blank Info Sec1: | 21110 |
| Blank Name Sec2: | Geocode |
| Blank Info Sec2: | 2107 |
| Timezone: | ICT |
| Utc Offset: | +7 |
| Coordinates: | 12.975°N 101.685°W |
Khao Chamao (Thai: เขาชะเมา, in Thai pronounced as /kʰǎw t͡ɕʰā.māw/) is a district (amphoe) of Rayong province, eastern Thailand.
The minor district (king amphoe) was split off from Klaeng district on 31 May 1993.[1]
On 15 May 2007, all 81 minor districts were upgraded to full districts.[2] With publication in the Royal Gazette on 24 August the upgrade became official.[3]
Neighboring districts are (from the north clockwise) Bo Thong of Chonburi province, Kaeng Hang Maeo of Chanthaburi province, and Klaeng and Wang Chan of Rayong Province.
The district is divided into four sub-districts (tambons), which are further subdivided into 21 villages (mubans). There are no municipal (thesabans), but there are four tambon administrative organizations (TAO).
| No. | Name | Thai name | Villages | Pop. | ||
|---|---|---|---|---|---|---|
| 1. | Nam Pen | น้ำเป็น | 7 | 7,025 | ||
| 2. | Huai Thap Mon | ห้วยทับมอญ | 8 | 7,419 | ||
| 3. | Cham Kho | ชำฆ้อ | 9 | 5,650 | ||
| 4. | Khao Noi | เขาน้อย | 5 | 2,338 |