A criminal charge of aiding and abetting is known as an accomplice crime, and may be brought against anyone who helps with the commission of a crime. Aiding and abetting charges vary from state to state (and under federal law), but generally require that the defendant knowingly and intentionally aided and abetted the principal(s) in each essential element of the underlying crime. A person charged with aiding and abetting is often not present when the underlying crime is committed, but has knowledge of the crime before the crime is committed, and assists with the commission of the crime by providing information, action, or financial support. If the person aiding and abetting has a sufficient degree of involvement in the crime, the participation may rise to the level of being a conspiracy to commit the underlying crime.

In Massachusetts, the concept of aiding and abetting is covered under the state's accomplice liability laws. An individual can be charged with aiding and abetting if they intentionally assist in the commission of a crime, even if they are not present during the actual perpetration of the crime. The assistance can be in the form of providing information, taking action, or offering financial support. To be convicted of aiding and abetting, the prosecution must prove that the defendant knowingly participated in the crime with the intent to commit it, and that their actions or advice were instrumental in the commission of the crime. The level of involvement can also lead to charges of conspiracy if it is determined that there was an agreement to commit the crime and an overt act in furtherance of that crime. Massachusetts law treats accomplices with the same severity as the principal offender, meaning that an aider and abettor can face the same penalties as the person who directly committed the offense.