International audience; Penguins face a wide range of threats. Most observed population changes havebeen negative and have happened over the last 60 years. Today, populations of 11penguin species are decreasing. Here we present a review that synthesizes detailsof threats faced by the world’s 18 species of penguins. We discuss alterations totheir environment at both breeding sites on land and at sea where they forage. Themajor drivers of change appear to be climate, and food web alterations by marinefisheries. In addition, we also consider other critical and/or emerging threats, namelyhuman disturbance near nesting sites, pollution due to oil, plastics and chemicals suchas mercury and persistent organic compounds. Finally, we assess the importance ofemerging pathogens and diseases on the health of penguins. We suggest that in the context of climate change, habitat degradation, introduced exotic species andresource competition with fisheries, successful conservation outcomes will require newand unprecedented levels of science and advocacy. Successful conservation storiesof penguin species across their geographical range have occurred where there hasbeen concerted effort across local, national and international boundaries to implementeffective conservation planning.