BAT may refer to:

• Bacula Administration Tool, an administration tool for the Bacula backup software
• Baby-AT computer case form factor, rarely abbreviated to BAT
• .bat, the filename extension used in DOS and Windows batch files
• Block Address Translation registers in PowerPC microprocessors

Bats are mammals of the order Chiroptera (; from the Greek χείρ - cheir, "hand" and πτερόν - pteron, "wing") whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, can only glide for short distances. Bats do not flap their entire forelimbs, as birds do, but instead flap their spread-out digits, which are very long and covered with a thin membrane or patagium.

Augusto Chaves Batista (15 June 1916 – 30 November 1967) was a Brazilian mycologist. He published more than 600 research papers, either alone or in collaboration with others. At the time of his death at the age of 51, Batista was the director of the Instituto de Micologia of the Federal University of Pernambuco.

A batch file is a kind of script file in DOS, OS/2 and Windows. It consists of a series of commands to be executed by the command line interpreter, stored in a plain text file. A batch file may contain any command the interpreter accepts interactively and use constructs that enable conditional branching and looping within the batch file, such as "if", "for", "goto" and labels.