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In many states the traditional distinctions between the culpability of accomplices and principals to a crime have been replaced by statute—including the felony murder rule that may make an accomplice guilty of first degree or capital murder if he was the lookout or getaway driver for a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 North Dakota, 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 is in line with the state's criminal code, which does not distinguish significantly between the person who directly commits the crime and those who aid, abet, or encourage the crime. Specifically, under North Dakota Century Code (NDCC) 12.1-03-01, a person is criminally liable for the conduct of another when acting with the kind of culpability required for the offense if they solicit, aid, abet, agree, or attempt to aid the other person in planning or committing the offense. The felony murder rule in North Dakota, as per NDCC 12.1-16-01, also states that an accomplice can be charged with murder if a death occurs during the commission of a felony, such as a bank robbery, even if the accomplice's role was limited to being a lookout or getaway driver. This means that accomplices face the same severe penalties as the principal offender, including the possibility of life imprisonment or other serious consequences.