After occurring sporadically in New Zealand since 1921, the common wasp,Vespula vulgaris(L.), was found in March and April 1983 to be established in Dunedin, where 6 nests were discovered. Subsequent examination of museum specimens showed that queens had been collected in Wellington in 1978, and nests by January 1982. Christchurch was invaded in early 1984, several workers were collected near Auckland in March and April 1984, and workers were reported at Nelson in March and May 1984. The Dunedin nests were up to 6 times the size of nests recorded from the Northern Hemisphere, and produced up to 23 times as many new queens. Workers, nest size, and nest productivity were sufficiently different from those reported in western North America to suggest that the New Zealand population originated elsewhere. Colour patterning of the head and pronotum readily separate New ZealandV. vulgarisfrom New ZealandV. germanica.The nest carton ofV. vulgarisis brown; that ofV. germanicais grey. Conditions in New Zealand appear to be favourable forV. vulgaris; it can be expected to spread and it may at times reach the high population levels experienced in Europe and the western United States.