The origin and evolution of Mars’s inventory of volatile elements is pivotal to a wide range of physical, chemical, geological, and biological issues and concerns. The identification of subglacially erupted volcanoes on Mars suggests that ice sheets existed at high and low latitudes repeatedly over geological time, but the importance of those volcanoes is not just as a simple Boolean climate signal. Like terrestrial subglacially erupted volcanoes, they can potentially yield a more holistic range of paleoenvironmental parameters, including ice thickness, thermal regime, and surface elevation. On Earth, at least nine different types of terrestrial subglacial volcanic successions can be identified using landform characteristics, lithofacies, and sequence architecture. The principal characteristics of each are reviewed in this paper, together with the first empirical comparative analysis of the morphometry of the landforms. All were probably erupted in association with wet-based ice and there are different implications for volcanic landforms erupted under different glacial thermal regimes (polar, subpolar). However, they represent our best sources of information with which to assess Mars analogs, some of which (as on Earth) may have been the source of megascale meltwater outburst floods. Applying the results of this paper to three different morphological types of candidate subglacial volcanoes on Mars indicates that it is difficult to suggest a plausible glaciovolcanic analogy for Mars’s tall cones; they more closely resemble pyroclastic mounds erupted subaerially or subaqueously, under ice-free conditions. Conversely, Mars’s low-domes may be very extensive, inflated, subglacial “interface sills” formed under comparatively thick ice of any thermal regime. Finally, the very large, flat-topped constructs on Mars resemble mafic tuyas emplaced in thick (up to 2 km) temperate ice. However, because of their very large size compared to terrestrial analogs, the possibility also exists that the latter are polygenetic stratovolcanoes, formed subglacially either within very thick ice, or as multiple superimposed lava-fed deltas emplaced in much thinner ice that repeatedly re-formed on the volcanoes after each eruptive episode. A plausible terrestrial analogy for the latter is the long-lived James Ross Island stratovolcano in Antarctica.