| Official Name: | Ajo |
| Pushpin Map: | Spain |
| Subdivision Type: | Country |
| Subdivision Name: |  Spain |
| Subdivision Type1: | Autonomous community |
| Subdivision Name1: | Cantabria |
| Subdivision Type2: | Province |
| Subdivision Name2: | Cantabria |
| Subdivision Type3: | Comarca |
| Subdivision Name3: | Trasmiera |
| Subdivision Type4: | Judicial district |
| Seat Type: | Capital |
| Leader Title: | Mayor |
| Leader Name: | D. José de la Hoz Lainz[1] |
| Population As Of: | 2008 |
| Population Total: | 1549 |
| Population Density Km2: | auto |
| Timezone: | CET |
| Utc Offset: | +1 |
| Timezone Dst: | CET |
| Utc Offset Dst: | +2 |
| Coordinates: | 43.4806°N -3.61°W |
| Elevation M: | 46 |
Ajo is the capital of Bareyo municipality in Cantabria, Spain. The town is 29km (18miles) from Santander.
The first historical written reference to Ajo (Asio) is in the "Liber Testamentarum" of Oviedo Cathedral from 923, in which the King Ordoño II of León donated the church of San Juan de Asio. Popular etymology without any basis says that the name comes from the great quantity of garlic that the town's inhabitants consumed and that gave the locality a typical smell.[2]
25% of the population of the municipality works in the primary sector, 19.1% in construction, 9.5% in industry and 46.4% in the services sector. The jobs of more than 78% of the population are related to the garlic industry.[3]
The municipal corporation has published since 2007 the Ojerada magazine, which reports on various activities in the municipality.[4] Since 2010, the municipality has a means of information managed by neighbors that has become a reference for local information in Cantabria. It is the Bareyo Digital or Bareyo Digital Media.