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In many states the traditional distinctions between the culpability of accomplices and principals to a crime have been replaced by statute—including the felony murder rule that may make an accomplice guilty of first degree or capital murder if he was the lookout or getaway driver for a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 Kentucky, the concept of a criminal accomplice is covered under the state's complicity laws. According to Kentucky law, a person is criminally liable as an accomplice if they intentionally aid, counsel, or attempt to aid another person in the planning or commission of a crime. This includes being present and actively participating in the crime, such as acting as a lookout or getaway driver during a bank robbery. Kentucky law does not distinguish between principals and accomplices in terms of culpability; both can be charged and convicted of the same crime. Furthermore, under Kentucky's application of the felony murder rule, an accomplice can be found guilty of 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 assistance rather than directly causing the death. This means that accomplices face the same severe penalties as the principal offender, including the possibility of first-degree or capital murder charges.