Trypophobia is an aversion to the sight of repetitive patterns or clusters of small holes or bumps. Although not clinically recognized as a separate mental or emotional disorder, trypophobia may fall under the category of 'specific phobia' in cases where it causes excessive fear or distress. Most sufferers normally experience mainly disgust when they see trypophobic imagery, although some experience equal levels of fear and disgust.

As of 2021, trypophobia is poorly understood by the scientific community. In the few studies that have taken place, several researchers hypothesized that it is the result of a biological revulsion, causing the afflicted to associate trypophobic shapes with danger or disease, and may therefore have some evolutionary basis, and that exposure therapy may be a possible treatment.

The term trypophobia was coined by an anonymous member of an online forum in 2005. It has since become a common topic on social networking sites.