| Official Name: | Katnaghbyur |
| Native Name: | Կաթնաղբյուր |
| Settlement Type: | Town |
| Pushpin Map: | Armenia |
| Mapsize: | 150px |
| Subdivision Type: | Country |
| Subdivision Name: | Armenia |
| Subdivision Type1: | Marz (Province) |
| Subdivision Name1: | Kotayk |
| Population As Of: | 2001 |
| Population Total: | 577 |
| Timezone: | |
| Utc Offset: | +4 |
| Timezone Dst: | |
| Utc Offset Dst: | +5 |
| Coordinates: | 40.2561°N 44.6767°W |
| Elevation M: | 1450 |
Katnaghbyur (Armenian: Կաթնաղբյուր, also Romanized as Kat’naghbyur, Katnaghbur, and Katnakhpyur; formerly, Agadzor, Agadarasi) is a town in the Kotayk Province of Armenia.