Ottawa Valley English is Canadian English of the Ottawa Valley, particularly in reference to the historical local varieties of the area, now largely in decline. The accents of such traditional varieties are commonly referred to as an Ottawa Valley twang or brogue. The Ottawa Valley historically extends along the Ottawa River from northwest of Montreal through the city of Ottawa and north of Algonquin Park. The Atlas of North American English identifies an Ottawa Valley traditional dialect enclave in Arnprior, which lacks the Canadian raising of /aʊ/ and strongly fronts /ɑ/ before /r/, but neither feature is documented in the City of Ottawa itself or in other nearby urban areas, which speak Standard Canadian English.^: 325

In the 1980s, linguist Ian Pringle and colleagues claimed that there was a huge variation in dialect features throughout the thinly-populated Ottawa Valley, notably with large Hiberno-English influence; however, the nature of such variation has never been thoroughly described. At a general phonetic level, the Ottawa Valley twang of Irish-descended people is characterized by raising of /aɪ/ and /aʊ/ in all contexts, as opposed to the Canadian English's more typical "Canadian raising", which is context-dependent. In terms of syntax, the twang features the use of "for to" in place of the "to" initiative.^: 279 Additionally, various regions of the Ottawa Valley may possess their own vocabularies (lexical features) as well.