Lampreys worldwide face multiple anthropogenic stressors. Several species are ‘at-risk’ listed, yet abundance data for most remain insufficient to adequately assess conservation status. Lamprey population declines are largely due to habitat degradation and fragmentation, pollution, and exploitation. Conservation priorities include: quantification of population trends and distribution; identification of Evolutionarily Significant Units; improved water quality and habitat; barrier removal or effective mitigation; ecologically-sensitive river flow management and hydropower planning; and mitigation of climate change impacts. There is urgent need for ecological and population demographics data for multiple species, particularly those in the Southern Hemisphere, Caspian Sea region, and Mexico. Irrigation and damming are already extensive, or rapidly expanding (e.g. Chile), while water-stressed regions (Mexico, California, Chile, Australia, Iberia) may be further impacted by climate change-induced flow alteration and increased temperatures. Barrier removal should benefit lampreys by increasing available habitat. However, fishways vary in effectiveness and are often inadequate, but present research opportunities encompassing ecohydraulics, biotelemetry and engineering. Environmental DNA permits rapid assessment of lamprey distribution within catchments, especially if improvements to distinguishing genetically similar groups are possible. Marine environments may play a critical role in population dynamics yet remain a “black box” in anadromous lamprey biology. Studying juvenile lamprey ecology is a substantial challenge but should be a priority. Some examples are monitoring of parasitic feeding-phase lamprey through trawl surveys and fisheries bycatch, telemetry of movements, or examining chemical tracers of marine habitat use. Knowledge transfer between the sea lamprey control programme and native-lamprey biologists worldwide remains crucial to developing effective lamprey management.