| Official Name: | Phachi |
| Native Name: | ภาชี |
| Native Name Lang: | th |
| Settlement Type: | District |
| Subdivision Type: | Country |
| Subdivision Name: | Thailand |
| Subdivision Type1: | Province |
| Subdivision Name1: | Ayutthaya |
| Subdivision Type2: | Seat |
| Subdivision Name2: | Phachi |
| Subdivision Type3: | Tambon |
| Subdivision Name3: | 8 |
| Subdivision Type4: | Muban |
| Established Title: | District established |
| Population Total: | 30481 |
| Population As Of: | 2000 |
| Blank Name Sec1: | Postal code |
| Blank Info Sec1: | 13140 |
| Blank Name Sec2: | Geocode |
| Blank Info Sec2: | 1409 |
| Timezone: | ICT |
| Utc Offset: | +7 |
| Coordinates: | 14.4492°N 100.7283°W |
Phachi (in Thai pronounced as /pʰāːt͡ɕʰīː/) is a district in the eastern part of Ayutthaya province.
The district was created in 1953, by separating it from Uthai district.
Phachi in Thai means 'divide' or 'junction', which refers to the railway junction between the northern and northeastern branches in the district.
Neighboring districts are (from the north clockwise) Tha Ruea of Ayutthaya Province; Nong Saeng and Nong Khae of Saraburi province; and Uthai and Nakhon Luang of Ayutthaya.
The district is divided into eight sub-districts (tambon).
| 1. | Phachi | ภาชี | ||
| 2. | Khok Muang | โคกม่วง | ||
| 3. | Rasom | ระโสม | ||
| 4. | Nong Nam Sai | หนองน้ำใส | ||
| 5. | Don Ya Nang | ดอนหญ้านาง | ||
| 6. | Phai Lom | ไผ่ล้อม | ||
| 7. | Krachio | กระจิว | ||
| 8. | Phra Kaeo | พระแก้ว |