| Official Name: | Nam Nao |
| Native Name: | น้ำหนาว |
| Native Name Lang: | th |
| Settlement Type: | District |
| Subdivision Type: | Country |
| Subdivision Name: | Thailand |
| Subdivision Type1: | Province |
| Subdivision Name1: | Phetchabun |
| Subdivision Type2: | Seat |
| Subdivision Name2: | Nam Nao |
| Subdivision Type3: | Tambon |
| Subdivision Type4: | Muban |
| Established Title: | District established |
| Population Total: | 15485 |
| Population As Of: | 2000 |
| Blank Name Sec1: | Postal code |
| Blank Info Sec1: | 67260 |
| Blank Name Sec2: | Geocode |
| Blank Info Sec2: | 6709 |
| Timezone: | ICT |
| Utc Offset: | +7 |
| Coordinates: | 16.7683°N 101.6717°W |
Nam Nao (Thai: น้ำหนาว, in Thai pronounced as /náːm nǎːw/) is the northeasternmost district (amphoe) of Phetchabun province, northern Thailand.
On 16 November 1978 the tambons Nam Nao and Lak Dan were split from Lom Sak district and made into a minor district (king amphoe).[1] It was upgraded to a full district on 19 July 1991.[2]
Neighboring districts are (from the north clockwise) Phu Luang and Phu Kradueng of Loei province, Phu Pha Man of Khon Kaen province, Khon San of Chaiyaphum province, and Lom Sak and Lom Kao of Phetchabun Province. The district's east side borders Phu Kradueng Mountain.
Nam Nao National Park is in the district.
The district is divided into four sub-districts (tambons), which are further subdivided into 30 villages (mubans). There are no municipal (thesabana) in the district. There are four tambon administrative organizations (TAO).
| 1. | Nam Nao | น้ำหนาว | ||
| 2. | Lak Dan | หลักด่าน | ||
| 3. | Wang Kwang | วังกวาง | ||
| 4. | Khok Mon | โคกมน |