BTB may refer to:

In biology:

• Blood–testis barrier in testicular anatomy
• Blood–thymus barrier
• Bovine tuberculosis or Mycobacterium bovis, a disease originating in cattle
• Breakthrough bleeding, of the menstrual period
• Bromothymol blue, a chemical indicator for weak acids and bases
• BTB/POZ domain, a protein domain

In other uses:

• Belgian Union of Transport Workers, a trade union in Belgium
• Branch target buffer, a computer processor element
• Bétou Airport, in the Republic of the Congo (IATA airport code: BTB)
• Basil Temple Blackwood (1870–1917), British book illustrator (credited as B.T.B.)
• Bob the Builder, British children's television series
• Board-to-board connector (BTB)

This disambiguation page lists articles associated with the title BTB.
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