Investigating the impacts of contamination on high latitude ecosystems includes determining the sensitivity of key taxa to contaminants. Unique characteristics, arising from adaption to cold and stable temperatures has likely resulted in marine biota at the poles being particularly sensitive to contamination in comparison to related species at lower latitudes. We aimed to determine the sensitivity of three species of common and ecologically important subantarctic gastropods to copper. This is the first study to investigate the sensitivity of subantarctic marine gastropods to contamination. We determined sensitivity by exposing each species to a range of copper concentrations by establishing mortality and sublethal endpoints. Sensitivity to copper was highly species specific. Laevilittorina caliginosa was relatively tolerant, with no response at Cu concentrations up to 1488 µg/L following 7 d of exposure, while two species (Cantharidus capillaceus coruscans and Macquariella hamiltoni) were highly sensitive with 7 d Cu LC50 estimates of 33 µg/L and 78 µg/L respectively. In a global comparison of gastropod sensitivity data, these two species were highly sensitive to copper, highlighting the vulnerability of polar ecosystems to contamination.