Boo Trend refers to a TikTok trend in which users say "boo" while crossing their eyes in mocking reference to the original video, typically making a funny face and moving toward the camera. The trend emerged online sometime around mid-to-late September 2026, spreading from TikTok to other social media platforms like Instagram.
The trend is commonly used as a prank by tricking people, especially boyfriends or family members, into performing the embarrassing trend alongside them and then only recording and posting their participation. Many examples also include edits or images of K-pop stars making similar facial expressions.