Hate speech comprises any form of hateful or contemptuous expression that attacks, degrades, or vilifies people based on their social identities. This Element focuses on hate speech targeting social identities that are devalued by a society's dominant groups, and that is likely to evoke, promote, or legitimize harms such violence, discrimination, and oppression. After detailing the ways in which hate speech is expressed (e.g., through derogatory labels, metaphors, offensive imagery), the production of hate speech is explored at theindividual level (e.g., prejudiced attitudes), group level (e.g., realistic intergroup threat), and societal level (e.g., hierarchy maintenance; free speech protections). A discussion of the effects of blatant and anonymous hate speech on targets (e.g., anxiety and depression) and nontargets (e.g., stereotype activation; desensitization; fomenting violence) follows. Finally, the effectiveness of mitigation efforts isexplored, including use of computer-based technologies, speech codes, confrontation, and counterspeech.