Macquarie Ridge is one of the southernmost seamount ridges, spanning 1600 kilometres from the southern tip of New Zealand to the Australia-Pacific-Antarctic triple junction halfway to Antarctica. Squat lobsters, superfamilies Chirostyloidea and Galatheoidea, are highly diverse at low and mid-latitudes, declining rapidly towards the poles; only 15 of the more than 1000 species have been recorded south of 50 degrees S. Prior to the present study, one species of squat lobster (Munidopsis pyrochela, Munidopsidae) was known from the Macquarie Ridge, but recent research voyages in 2003 and 2008 collected a further five species from both superfamilies and three families. Uroptychus tracey (Chirostylidae) is new to science. Uroptychus insignis (Henderson, 1885) is reported for the first time outside of the western Indian Ocean and re-described based on type material. Subtle differences between the western Indian Ocean and Macquarie Ridge specimens of U. insignis suggest that the latter specimens might represent a separate species. Munida chathamensis Baba, 1974 (Munididae) is re-described and reported for the first time outside of its Chatham Rise type locality. New morphological variation is reported for Munida isos. Munidopsis tasmaniae is reported not only for the first time from the Macquarie Ridge, but also for the first time from New Zealand waters.