A Halligan bar (also called a Halligan tool or Hallagan, and is often referred to as a Hooligan Tool in various British and Australian fire services) is a special forcible entry tool commonly used by firefighters and law enforcement. It was designed by and named after Hugh Halligan, a First Deputy Fire Chief in the New York City Fire Department, in 1948. While the tool was developed by a Deputy Chief of the New York City Fire Department, the department did not initially purchase it because of a perceived conflict of interest in buying from a member of the department. The City of Boston Fire Department was the first major customer of the tool, purchasing one for every fire company in their city. The tool was popular enough that members of New York ladder companies went out and bought it with their own money until the department ultimately decided to purchase the tool.

The Halligan is based on the earlier Kelly tool. The Halligan is a multipurpose tool for prying, twisting, punching, or striking. It consists of a claw (or fork), a blade (wedge or adze), and a tapered pick, which is especially useful in quickly breaching many types of locked doors. Either the adze end or fork end of the tool can be used to break through the latch of a swinging door by forcing the tool between the door and door jamb and prying the two apart, striking it with another Halligan, a Denver tool, a sledgehammer or a flat-head axe. The pick can be placed into the shackle (or eye) of a padlock or hasp and twisted or pried to break it free. It can also be driven into a roof to provide a foothold for firefighters engaged in vertical ventilation. Using a K-tool and the adze end, a lock cylinder can easily be pulled. The fork end is routinely used to shut off gas meter valves. There are many other uses of the Halligan tool, including vehicle extrication and opening of walls.