The United Church in Papua New Guinea and the Solomon Islands is merged denomination dating from 1968 consisting of the former London Missionary Society (operating exclusively in Papua), the relatively marginal Presbyterian church (largely confined to Port Moresby itself) and the Methodist mission (largely operating in the New Guinea Islands, the western and northern Solomons and the islands of eastern Papua).

Its formation pre-dates the merger of its corresponding (and missionary parent) denominations in Australia in 1975 in the Uniting Church in Australia but such cross-denominational mergers were common throughout the 20th century, particularly in Commonwealth countries: for example, the "United Church of North India" (1924) (now known as the Church of North India) and later the Church of Pakistan); the United Church of Canada (1925) and the Church of South India (1947). It is particularly strong on the Papuan coast, the Southern Highlands, eastern Papua, the New Guinea Islands (including Bougainville, also known as the North Solomons) and the Western Solomons.