Klemtu is the home of the Kitasoo tribe of Tsimshians, originally from Kitasu Bay, and the Xai'xais of Kynoch Inlet, a subgroup of the Heiltsuk people. These two tribes live together as, and are jointly governed by, the Kitasoo/Xai'xais Nation. Traditional languages spoken at Klemtu are the southern dialect of the Tsimshian language, called Southern Tsimshian, and Xaixais, a dialect of the Heiltsuk language. In religious affiliation, the community is dominated by the United Church of Canada.
The government of the Kitasoo/Xai'xais Nation is a member government of the Oweekeno-Kitasoo-Nuxalk Tribal Council.
The population of Klemtu in 1983 was 269. the population of Klemtu was 505.