A riot shield is a lightweight protection device, typically deployed by police and some military organizations, though also utilized by protestors. Riot shields are typically long enough to cover an average-sized person from the top of the head to the knees, though smaller one-handed models may also be used. They are generally intended to be used in riot control, to protect the user from melee attacks with blunt or edged weapons and also thrown projectiles, or non-lethal weapons such as rubber bullets and water cannons. They can also be used as short-ranged melee weapons to push back the opposing force. Most riot shields do not offer ballistic protection; ballistic shields are instead used in situations where heavily armed resistance is expected.

Riot shields are used in almost every country with a standardized police force and are produced by many companies. Law enforcement often use them in conjunction with a baton. Riot shields made for law enforcement are typically constructed from transparent polycarbonate to enable the bearer to see incoming thrown objects. Riot shields used by protesters are often constructed from improvised materials, such as wood, scrap metal or plastic barrels. While riot shields are shown to be effective in protecting the bearers and preventing protesters from breaking through police lines, their use may actually encourage people to throw objects.