| Official Name: | Sai Yok |
| Native Name: | ไทรโยค |
| Native Name Lang: | th |
| Settlement Type: | District |
| Subdivision Type: | Country |
| Subdivision Name: | Thailand |
| Subdivision Type1: | Province |
| Subdivision Name1: | Kanchanaburi |
| Subdivision Type2: | Seat |
| Subdivision Type3: | Tambon |
| Subdivision Name3: | 7 |
| Subdivision Type4: | Muban |
| Subdivision Name4: | 57 |
| Established Title: | District established |
| Population Total: | 62212 |
| Population As Of: | 2015 |
| Blank Name Sec1: | Postal code |
| Blank Info Sec1: | 71150 |
| Blank Name Sec2: | Geocode |
| Blank Info Sec2: | 7102 |
| Timezone: | ICT |
| Utc Offset: | +7 |
| Coordinates: | 14.1156°N 99.1444°W |
Sai Yok (Thai: ไทรโยค, in Thai pronounced as /sāj jôːk/) is a district (amphoe) in Kanchanaburi province in western Thailand.
The district is in the valley of the Khwae Noi River in the Tenasserim Hills area. It borders Myanmar to the south. Along the river the Death Railway runs to Nam Tok Sai Yok Noi.
Sai Yok National Park was created on 27 October 1980 and covers an area of about 500 km2. The most famous sight in the park is the Sai Yok waterfall.
Neighboring districts are (from north clockwise) Thong Pha Phum, Si Sawat, Mueang Kanchanaburi of Kanchanaburi Province and Tanintharyi Division of Myanmar.
Apart from the nature of the Kwae Noi River valley, the other main attraction is Mueang Sing Historical Park, which shows the westernmost Khmer-style temple complex. Also popular for tourists is the Tiger Temple.
Sai Yok is divided into seven sub-districts (tambons), which are further subdivided into 57 administrative villages (mubans).
| No. | Name | Thai | Villages | Pop.[1] | |
|---|---|---|---|---|---|
| 1. | Lum Sum | Thai: ลุ่มสุ่ม | 11 | 10,580 | |
| 2. | Tha Sao | Thai: ท่าเสา | 11 | 13,584 | |
| 3. | Sing | Thai: สิงห์ | 6 | 4,805 | |
| 4. | Sai Yok | Thai: ไทรโยค | 8 | 10,449 | |
| 5. | Wang Krachae | Thai: วังกระแจะ | 9 | 9,134 | |
| 6. | Si Mongkhon | Thai: ศรีมงคล | 8 | 7,840 | |
| 7. | Bongti | Thai: บ้องตี้ | 4 | 5,820 |
There are three sub-district municipalities (thesaban tambons) in the district:
There are six sub-district administrative organizations (SAO) in the district: