Believer's Baptism is the Christian ritual of baptism as given only to adolescents or adults who first proclaim to believe in Jesus Christ as their personal savior who died for their sins and was resurrected by God. Whereas Catholics, Eastern Orthodox, and many Protestant churches baptize infant children of believers (see pedobaptism), Believer's Baptism can only be administered to someone over the age of consent, which is usually 8-12, depending on the individual church. Sometimes there is no set age of consent, but instead each child wanting to be baptized will be interviewed by a pastor who determines whether the child is old enough to understand what they are doing, and if they truly believe their profession of faith. Thus, intellectual understanding and agreement are prerequisites for baptism according to this view.

Believer's Baptism in some denominations is also associated with the idea that baptism is necessary to gain full access to the local church. This is generally the case with churches that use a congregational form of church government. People who want to become part of that church must undergo Believer's Baptism in the local church, or a church that has been determined to have the same beliefs, before they can become a member. Typically those who were baptized in another church of like faith and practice gain membership in a local church with either the process known as 'membership by letter' or that of 'membership by statement', depending if the other church is still in existence or not.

Believer's Baptism is one of several distinctives associated with the Baptist and Anabaptist churches.