| Ba Phnum | |
| Native Name: | Central Khmer: បាភ្នំ |
| Official Name: | Ba Phnum District Central Khmer: ស្រុកបាភ្នំ |
| Settlement Type: | District |
| Pushpin Map: | Cambodia |
| Pushpin Label Position: | bottom |
| Pushpin Map Caption: | Location in Cambodia |
| Subdivision Type: | Country |
| Subdivision Name: |  Cambodia |
| Subdivision Type1: | Province |
| Subdivision Name1: | Prey Veng |
| Population As Of: | 1998 |
| Population Footnotes: | [1] |
| Population Total: | 71,662 |
| Timezone: | ICT |
| Utc Offset: | +7 |
| Coordinates: | 11.2333°N 127°W |
| Geocode: | 1401 |
Ba Phnum (Central Khmer: បាភ្នំ, in Central Khmer pronounced as /baːpʰnum/), sometime spelled as Ba Phnom, is a district located in Prey Veng Province, in south eastern Cambodia. The hills surrounding the town are the highest elevation points in Prey Veng province. In Khmer, Ba means "ancestor" and Phnum means "hill." When combined, the town is known as "Hill of the Ancestors."
Ba Phnum is a relatively remote location and has been attractive to ascenti monks (loak dhutang) for centuries. It has also been an occasional center from which millennial movements have radiated throughout Khmer history.
Ba Phnum is a site of interest for Cambodian historians. According to some accounts, the area is the birthplace of the Khmer people. An inscription on Wat Jaan, the pre-Angkorian temple at the base of the mountain (ca. 629 AD), associates Ba Phnum with Shiva and refers to it as "the holy mountain."
Ba Phnum was prominently featured in many of the rural scenes in the 2016 documentary Angkor Awakens.
Human sacrifices were made here until 1872. Khmer Kings made pilgrimage here.
Ba Phnum has purportedly been the location of Vyadhapura, capital of the kingdom of Funan.