A criminal accomplice is a person who knowingly, voluntarily, or intentionally assists another person in the commission of a crime—or under some circumstances, a person who fails to prevent another person from committing a crime. Unlike a person who aids and abets a crime by helping with the planning of the crime but is often not present at the scene of the crime—and unlike an accessory after the fact, who is not present at the scene of the crime but assists after the commission of the crime to help the perpetrator avoid arrest or punishment—an accomplice actively participates in the commission of the crime. For example, a person who acts as a lookout or getaway driver for a bank robbery is an accomplice.

In many states the traditional distinctions between the culpability of accomplices and principals to a crime have been replaced by statute—including the felony murder rule that may make an accomplice guilty of first degree or capital murder if he was the lookout or getaway driver for a bank robbery that resulted in a death.

In Oklahoma, an individual who assists in the commission of a crime is considered an accomplice and can be charged and punished as if they were the principal offender. This includes those who aid, abet, encourage, or facilitate the commission of the crime, such as lookouts or getaway drivers. Oklahoma law does not distinguish significantly between the principal and the accomplice in terms of culpability; both can face the same charges and penalties. Under Oklahoma's felony murder statute, if a death occurs during the commission of certain felonies, including a bank robbery, all participants can be charged with first-degree murder, regardless of their role in the crime. This means that an accomplice to a felony that results in death can face severe penalties, including life imprisonment or the death penalty, even if they did not directly cause the death.