| Javary River | |
| Name Other: | Javari River |
| Map Size: | 300 |
| Pushpin Map Size: | 300 |
| Subdivision Type1: | Country |
| Subdivision Name1: | Brazil, Peru |
| Length: | [1] |
| Discharge1 Location: | Benjamin Constant, Amazonas State (near mouth) |
| Discharge1 Avg: | (Period: 1971–2000)[2] [3] (Period: 1973–1990)[4] [5] |
| Source1 Location: | Sierra de Contamana, Ucayali, Peru |
| Source1 Elevation: | [6] |
| Mouth: | Amazon River |
| Mouth Location: | Amazonas, Brazil |
| Mouth Coordinates: | -4.3828°N -70.0308°W |
| Mouth Elevation: | [7] |
| Progression: | Amazon → Atlantic Ocean |
| River System: | Solimões |
| Basin Size: | to [8] |
| Tributaries Right: | Gálvez, Yavari-Mirim |
| Discharge2 Location: | Estirão do Repouso, Amazonas State (Basin size: |
| Discharge2 Avg: | (Period of data: 1970–1996)[9] |
The Javary River, Javari River or Yavarí River (Spanish; Castilian: Río Yavarí|links=no; Portuguese: Rio Javari|links=no) is a tributary of the Amazon that forms the boundary between Brazil and Peru for more than .[10] It is navigable by canoe for from above its mouth to its source in the Ucayali highlands, but only 260 were found suitable for steam navigation.
The Brazilian Boundary Commission ascended it in 1866 to the junction of the Shino with its Jaquirana branch. The country it traverses in its extremely sinuous course is very level, similar in character to that of the Juruá.
There are a number of small private reserves along the river, which arrange wildlife viewing.[11]
The town of Benjamin Constant lies at the mouth of the river, on the Brazilian bank.