PBO

• Paperback original, a book originally published as paperback
• PbO, the chemical formula for lead(II) oxide
• Pine Bluff Observatory, an astronomical observatory in Wisconsin, USA
• Pinoy Box Office, a 24-hour Filipino Movie cable channel
• Piperonyl butoxide, a pesticide synergist
• Plate Boundary Observatory PBO, a geodetic observatory in the western United States
• Polybenzobisoxazole, a strong heat-resistant polymer; also known as Zylon

PBO may also stand for:

• The IATA airport code for Paraburdoo Airport, Paraburdoo, Australia
• The UK train station code for Peterborough railway station