Diprion similis is a species of sawfly in the family Diprionidae. It is native to central and northern Europe and Asia but has been accidentally introduced into North America where it has become invasive. The larvae feed on the needles of pine trees, especially those of the white pine (Pinus strobus). In North America it is known as the introduced pine sawfly or the imported pine sawfly. It is also known as the white pine sawfly because of its preference for feeding on the white pine, but this name is confusing because another sawfly, Neodiprion pinetum, whose larvae also feed on this tree, is itself known as the "white pine sawfly".