Bab or BAB can refer to:

• Bab (toponymy), a component of Arabic toponyms literally meaning "gate"
• Set (mythology) (also known as Bab, Baba, or Seth) ancient Egyptian God
• Bab (Shia Islam), a term designating deputies of the Imams in Shia Islam
• Báb (Sayyid `Alí Muḥammad Shírází, 1819–1850), founder of Bábism and a central figure in the Bahá'í Faith
• Bab-ı Âli, the gate to the palace of the Grand vizier of the Ottoman Empire
• Báb, Nitra District, a village and municipality in the Nitra District in western central Slovakia
• Bab Ballads, cartoons published by W. S. Gilbert under the childhood nickname, Bab
• Back-arc basin, a geologic feature: a submarine basin associated with island arcs and subduction zones
• "Base Attack Bonus", a term used in d20 System RPG games
• Beale Air Force Base (IATA airport code: BAB), in California
• Biotechnology and Applied Biochemistry, an academic journal
• Boris Berezovsky (businessman) (1946–2013), Boris Abramovich Berezovsky, a powerful Russian oligarch in self-imposed exile in London from 2001
• Build America Bonds, a type of municipal bond created by the American Recovery and Reinvestment Act of 2009
• Bunty Aur Babli, a 2005 Indian film
• German autobahns or Bundesautobahn, federal motorways in Germany
• B. A. Baracus, character on 1980s action series The A-Team
• The British Aikido Board, a federation of independent Aikido associations within the United Kingdom
• Babcock International (stock symbol BAB)
• Balcombe railway station, a railway station in Sussex, England