Aboriginal English has been documented in widely separated parts of Australia and, despite some stylistic and regional variation, is remarkably consistent across the continent, and provides a vehicle for the common expression of Aboriginal identity. There is, however, some indeterminacy in the way in which the term is used in much academic and public discourse. There are diverse assumptions as to its relation to pidgin, creole and interlanguage varieties, as well as to Australian English. In an attempt to provide some clarification, this paper compares Aboriginal English with the main varieties with which it bears some relationship, either historically (as in the case of the English of Southeast England and Ireland) or geographically (as in the case of Australian English and Australian pidgins and creoles). It does this by employing the morphosyntactic database of the "World Atlas of Varieties of English" (Kortmann & Lunkenheimer, 2012). The electronic database on morphosyntactic variation in varieties of spoken English (eWAVE) isolates 235 variable features and enables their relative prevalence to be compared across varieties. A comparison of Aboriginal English with six relevant varieties on this database leads to the view that it retains significant influence from the English varieties of Southeast England and of Ireland, in many ways not shared with Australian English and that it has a great deal more feature overlap with Australian creoles than with Australian English, though a significant percentage of its features is shared only with other English varieties rather than creoles. The findings support the view that Aboriginal English is an English variety of post-creole origin, though not a creole, and that it is not directly related to Australian English. In the light of these findings, it is argued that Aboriginal English speakers will be disadvantaged in an education system which assumes that they are speakers of Australian English.