At law, an accomplice is a person who actively participates in the commission of a crime, even though they take no part in the actual criminal offence. For example, in a bank robbery, the person who points the gun at the teller and asks for the money is guilty of armed robbery. However, anyone else directly involved in the commission of the crime, such as the lookout, a second gunman, or the getaway car driver, is an accomplice, even though in the absence of an underlying offence keeping a lookout, holding a gun, or driving a car would not be an offence.

At law, an accomplice has the same degree of guilt as the person they are assisting and is subject to prosecution for the same crime and faces the same criminal penalties. As such, the three accomplices to the bank robbery above can also be found guilty of armed robbery even though only one stole the money.

An accomplice must be distinguished from an accessory, even though in both cases they are guilty of the same offence as the person who commits the crime. Accessories may supply aid to the criminal enterprise, but are not directly involved in its planning and execution. For example, the person who gave the bank robbers their guns is an accessory before the fact. The person who launders the money afterwards in an accessory after the fact.

Accomplices must also be distinguished from co-conspirators , even though again in both cases they are subject to prosecution for the same offence. A conspirator is involved in the planning of a criminal offence, and, as such, may be an accomplice, but is not necessarily an accomplice.

The fairness of the doctrine that the accomplice is as guilty as the primary offender has been discussed many times, particularly in cases of capital crimes . On several occassions, accomplices have been prosecuted for felony murder even though the actual person who committed the murder died at the crime scene or otherwise did not face capital punishment. One of the most notorious cases of this type was the 1952 case in England involving Derek Bentley, a mentally-challenged man who was in police custody when his sixteen-year-old companion, Chris Craig, shot and killed a police officer during a botched break-in (News Report [1]). Craig received life imprisonment as he could not be sentenced to death as a juvenile offender (he was released after serving only ten years), but Bentley was hanged. The incident was dramatized in the film Let Him Have It , which is what Bentley allegedly said to Craig during the incident, it being unclear whether he meant to shoot the officer or to hand the gun to him. The hanging of Bentley led to public outrage and the eventual abolition of capital punishment in the United Kingdom.