Populations of goldenrods (Solidago canadensis) were sampled to determine the effects of three stem gall insects, Gnorimoshema gallaesolidaginis (Gelechiidae), Eurosta solidaginis (Tephritidae), and Rhopalomyia solidaginis (Cecidomyiidae) on resource allocation patterns in the plants. Gall infestations were as high as 38.5% and the dominant gall insect differed from site to site. The gall insects caused significant and highly specific effects on the plants. Each of the three gall types increased stem production, decreased current rhizome production, and lowered seed reproductive allocation as measured both by inflorescence production and propagule production. Vegetative reproductive allocation (the proportion of biomass allocated to new rhizome) was unaffected. With the exception of ball gall—beaing ramets, the number of new rhizomes produced was unaffected by the presence of galls. Growth of the elliptical gall significantly reduced shoot height and significantly increased lateral branching and propagule weight. Formation of the ball significantly reduced propagule weight and the number of new rhizomes produced. Thus gall insect—plant interactions may play an important role in the evolution of plant life history patterns in certain taxa. Future studies are needed to determine the effects of galls on entire clones (genets) and the implications of gall infestation on future growth, survivorship, and reproduction.