霸凌（英语：Bullying），又称欺负，指的是一种长时间持续的、并对个人在心理、身体和言语遭受恶意的攻击，且因为欺凌者与受害者之间的权力或体型等因素不对等，而不敢或无法有效的反抗。霸凌的欺凌者可以是个人，也可以是群体，透过对受害人身心的压迫，造成受害人感到愤怒、痛苦、羞耻、尴尬、恐惧、以及忧郁。而霸凌所带来的伤害往往是不可逆转的。霸凌可能发生在校园、职场、甚至在互联网上。随着科技进步，即时通信软件、网络论坛、BBS、博客等交流平台也成为霸凌事件的发生场所，欺凌者藉网络或电信设备以文本和多媒体长期、反复攻击受害人，称为网络霸凌（Cyberbullying）。

Bullying is the use of force, threat, or coercion to abuse, intimidate, or aggressively dominate others. The behavior is often repeated and habitual. One essential prerequisite is the pe****tion, by the bully or by others, of an imbalance of social or physical power, which distinguishes bullying from conflict. Behaviors used to assert such domination can include verbal harassment or threat, physical assault or coercion, and such acts may be directed repeatedly towards particular targets. Rationalizations for such behavior sometimes include differences of social class, race, religion, gender, sexual orientation, appearance, behavior, body language, personality, reputation, lineage, strength, size or ability. If bullying is done by a group, it is called mobbing.