The dialect or dialects of Hokkaido (北海道方言, Hokkaidō-hōgen), commonly called Hokkaidō-ben (北海道弁), originate in relatively recent settlement from mainland Japan. The greater part of Hokkaidō was settled from a mix of areas, especially the Tōhoku and Hokuriku regions, from the Meiji period onwards, so that various Japanese dialects became mixed together on Hokkaidō.

The relationship of Hokkaidō dialect to the rest of Japanese—and whether there even is a coherent Hokkaidō dialect—are the subject of debate. Shibata (2003) mentions three theories:^[1]

1. Inland varieties are part of the Kantō dialect, while coastal varieties are part of the Tōhoku dialect
2. There is a single Hokkaidō dialect, which is a distinct branch of Eastern Japanese
3. There is a Hokkaidō dialect, but it descends from Niigata dialect (one of the Tōkai–Tōsan dialects), a transitional form with Western Japanese features.

Tōhoku influence is strongest in coastal areas, especially on the Oshima Peninsula in the south, where the local variety is commonly called Hama-kotoba (浜言葉, seashore speech). The urban dialect of Sapporo is quite close to Standard Japanese. Western features may have been brought by merchants from Kansai and Hokuriku following the Kitamaebune ("northern-bound ships") trading route.

Also spoken on Hokkaidō is the Ainu language, which was in wide use there before Japanese settlement and still has a few elderly speakers.