CTB may refer to:
- CTB/McGraw-Hill, a division of the McGraw-Hill Companies
- California Testing Bureau, a division of the McGraw-Hill Companies
- Ceylon Transport Board, the nationalised passenger transport venture in Sri Lanka
- Cooper Tire & Rubber Company's NYSE ticker symbol
- Ryan Giggs or CTB, the claimant in CTB v News Group Newspapers and CTB v. Twitter Inc., Persons Unknown
- Crash Thunder Buster, a finishing move of Jushin "Thunder" Liger
- Christchurch Transport Board, a defunct municipal public transport operator in Christchurch, New Zealand