The felony murder rule is a legal doctrine that expands the definition of murder and makes criminal accomplices (including a lookout or getaway driver) as responsible for a death that occurs in the course of a dangerous felony crime as the person who directly caused the death by pulling the trigger of a gun, stabbing the victim with a knife, strangling the victim, or otherwise causing the victim’s death. Examples of dangerous felony crimes that implicate the felony murder rule include robbery, burglary, rape, aggravated kidnapping, carjacking, and arson.

When the felony murder rule applies, it may make a criminal accomplice liable for murder even if the criminals had agreed that no one would be killed in the course of the crime, and even if it is a fellow criminal who is killed in the course of the crime—such as when a police officer or security guard shoots a bank robber—which may result in all other accomplices to the crime being charged with murder.

In many states the felony murder rule—and any distinctions between the culpability of accomplices and principals to a crime—are located in the state’s statutes—often in the penal or criminal code.

In Maryland, the felony murder rule is codified in the state's criminal law statutes. This rule allows for an individual to be charged with murder if they or an accomplice kill someone, even unintentionally, during the commission of certain felonies. The felonies that can trigger the felony murder rule in Maryland typically include violent crimes such as arson, carjacking, rape, robbery, burglary, and kidnapping. Under this doctrine, all participants in the felony can be held equally responsible for a death that occurs during the commission of the felony, regardless of who actually committed the lethal act. This means that a lookout or getaway driver can be charged with murder if a death occurs, even if they did not directly cause it. The rule applies whether the victim is an innocent party or a co-felon, such as in a situation where a police officer kills one of the robbers during a bank heist. The intent to kill is not a necessary element for a felony murder charge under this rule; the mere fact that a death occurred during the commission of a qualifying felony is sufficient to elevate the charge to murder for all involved in the underlying crime.