In high-altitude rangeland environments in Nepal and other Himalayan countries, grazing by domestic livestock poses a threat to local wildlife, in terms of competition for resources and other deleterious changes in behaviour. An experimental approach (before-during-after design) was used to investigate the effects of disturbance by livestock and attending herder on the behaviour of the Himalayan marmot (Marmota himalayana)—a common burrowing animal. When disturbed by livestock and herder, marmots reduced their foraging activities and conversely increased vigilance levels. After livestock and herder had departed from a marmot colony, the marmots mostly returned to their normal behaviour; however, prolonged vigilance activity was observed. Marmots appear to have habituated to livestock and herder to some extent, but still responding to the livestock and herder by modifying their behaviour. Increased vigilance behaviour at the expense of foraging time may have potential consequences in terms of meeting energy budgets for winter hibernation. Therefore, future increases in livestock numbers could have a deleterious effect on marmots and other ground-dwelling wildlife in the region.