A mafia boss, also known as a crime boss, is a person in charge of a criminal organization. The term "mafia boss" is often used to refer to the head of a mafia or organized crime family. The boss is the top decision maker and has the power to promote or demote family members at will. They also have the sole power to sanction murders inside and outside the family. In the Sicilian and Italian-American Mafia, the boss is the head of the crime family. The boss can initiate an associate into the family, allowing them to become a made man, and only the boss, underboss, or consigliere can do so. When a boss dies, the crime family members choose a new boss from inside the organization.

The American Mafia, also known as the Italian American Mafia, is a highly organized Italian American criminal society and organized crime group. The organization is often referred to as Cosa Nostra, which means "our thing" or "this thing of ours" in Italian. The bosses of the most powerful families have equal say and vote on important matters and solve disputes between families through The Commission, which was created in 1931. The Commission ruled over the National Crime Syndicate and brought an era of peace and prosperity for the American Mafia. The Mafia has controlled unions all over the U.S. and has enlisted many members in unions, even making them union executives. All mobsters within the Mafia, except associates, are "made" official members of a crime family, and the three highest positions make them untouchable in the criminal underworld.