Social isolation in stabled horses is thought to be a contributing factor to weaving, a common locomotor stereotypy. The purpose of this study was to determine if providing mirrors would relieve the sense of social isolation felt by the horses, as they would think their conspecifics were nearby. The behaviour of six horses was recorded for one week prior to the exposure to mirrors. For the five weeks following the initial week of observations, three horses were exposed to mirrors and three were not. The mirrors were then switched, such that the horses that were not exposed to mirrors became exposed, and those that had been exposed were not. The behaviour of the horses was then recorded for five more weeks. The experiment ended with none of the horses being exposed to mirrors and their behaviour was recorded for one week. The results indicated that the mirror significantly reduced the problem behaviours of weaving and nodding, but did not affect the time spent standing active, dozing or ingesting. The use of mirrors to treat weaving and nodding problems appears to be more effective than other treatments including weaving bars.