Abstract The aim of this study is to identify the major characteristics of demographic ageing in the Canadian Arctic — Yukon, Nunavut, and Northwest Territories (NWT) — in the period 1950 to 2050. We measure ageing first conventionally, based on ”chronological” age, as a point of comparison for results obtained applying new measures of ageing based on ”prospective” age. The latter takes into account upward changes in life expectancy and longevity over recent decades. The findings are discussed for the territories with the oldest and youngest average ages, the regions ageing the fastest and slowest, for both sexes and (to some extent) across ethnic differences. The paper considers whether the territories of Arctic Canada are converging or diverging in their ageing pathways and the links between the northern and nationwide patterns were traced. We find that NWT and Nunavut are the youngest and are diverging from nationwide ageing dynamics while Yukon is no longer different from the rest of Canada. The results of this study can help devise policies for coping with the population ageing in the Arctic part of Canada.