The Deceangli or Deceangi (Welsh: Tegeingl) were one of the Celtic tribes living in Britain, prior to the Roman invasion of the island. The tribe lived mainly in what is now north-east Wales, though it is uncertain whether their territory covered only the modern counties of Flintshire,Denbighshire and part of Cheshire in what is now present day England or whether it extended further west. The tribe occupied an area between the Clwyd and Dee rivers. They lived in hill forts running in a chain through the Clwydian Range and their tribal capital was Canovium.
Assaults on the Welsh tribes were made under the legate Publius Ostorius Scapula who attacked the Deceangli in 48 AD. They appear to have surrendered with little resistance, unlike the Silures and the Ordovices who put up a long and bitter resistance to Roman rule. No Roman town is known to have existed in the territory of this tribe, though the auxiliary fort of Canovium (Caerhun) was probably in their lands and may have had a civilian settlement around it.