<p>Mountains are home to some of the most spectacular biodiversity on Earth, but mountain species are thought to be especially vulnerable to climate change-driven extinctions. However, mountains can also be refugia, providing a plethora of habitats and climates that allow species to persist despite climate change. In this Review, we examine how mountain species have responded to past and ongoing warming to assess their vulnerability and resilience to climate change. We highlight three main take-home messages. First, mountain species largely showed resilience in response to Quaternary warming: species showed variable responses over short timescales, but communities generally tracked temperature changes over longer timescales, with little evidence of climate-driven extinctions. Second, mountain species show a mix of vulnerability and resilience in response to modern anthropogenic warming: species show variable elevational range changes, and there are cases of mountaintop extirpations. Third, vulnerability to modern climate change appears to be most pronounced in tropical species, high-elevation species and species whose ecological traits are associated with greater climate exposure. Both Quaternary and modern data reveal that mountain species can be much more resilient than often assumed by standard forecasting approaches, but accumulating evidence suggests many tropical mountain species are vulnerable to current warming.</p>