Adult Thysanoptera occur within plant galls for various reasons and use of the term “gall-thrips” without defining the particular relationship is uninformative and misleading. Apart from inducing a gall, a thrips may be found in a gall as a predator feeding on the galler, as a kleptoparasite feeding on plant cells and usurping the protective space induced by the galler, as a phytophagous inquiline breeding in low numbers in a gall without disturbing the galler, or as a casual visitor seeking protection from desiccation. These various relationships are discussed in the light of how little is known about the phylogenetic relationships amongst the Phlaeothripidae, the thrips family that includes most of the galling thrips species. Host associations amongst thrips, including the galling habit, are largely opportunistic, with few examples of a close relationship between thrips and plants above the level of genus in either group.