The Sinner's prayer (also called the Consecration prayer and Salvation prayer) is an evangelical Christian term referring to any prayer of repentance, prayed by individuals who feel sin in their lives and have the desire to form or renew a personal relationship with God through Jesus Christ. It is a popular prayer in evangelical circles. It is not intended as liturgical like a creed or a confiteor said or chanted within the Catholic Mass, but rather, is intended to be an act of initial conversion to Christianity; at the same time, it is roughly analogous to the Catholic Act of Contrition, though the theology behind each is markedly different, due to the intrinsically different views of salvation between Catholicism and Protestantism. While some Christians see reciting the sinner's prayer as the moment defining one's salvation, others see it as a beginning step of one's lifelong faith journey.

It also may be prayed as an act of "re-commitment" for those who are already believers in the faith. Often, at the end of a worship service, in what is known as an altar call, a minister or other worship leader will invite those desiring to receive Christ (thus becoming born again) to repeat with him or her the words of some form of a sinner's prayer. It also is frequently found on printed gospel tracts, urging people to "repeat these words from the bottom of your heart".

The Sinner's prayer takes various forms, all of which have the same general thrust. Since it is considered a matter of one's personal will, it can be prayed silently, aloud, read from a suggested model, or repeated after someone modeling the prayer role. There is no formula of specific words considered essential, although it usually contains an admission of sin and a petition asking that Jesus enter into the person's heart (that is to say, the center of their life). The use of the sinner's prayer is common within some Protestant denominations, such as Baptist Churches and Methodist Churches, as well as in movements that span several denominations, including evangelical, fundamentalist, and charismatic Christianity. It has also been used, though not as widely, by some Anglicans, Lutherans, and Roman Catholics. It is sometimes uttered by Christians seeking redemption or reaffirming their faith in Christ during a crisis or disaster, when death may be imminent.

Because no such prayer or conversion is found in the Bible, some biblical scholars have critiqued the sinner's prayer, calling it a "cataract of nonsense" and an "apostasy". David Platt has raised questions over the authenticity of the conversions of people using the Sinner's prayer based on research by George Barna.