Woi or WOI may refer to:

• WOI (AM), a radio station (640 AM) in Ames, Iowa
• WOI-FM, a radio station (90.1 FM) Ames, Iowa
• WOI-DT, a television station in Ames, Iowa
• Warrant Officer Class I, a rank in the British Armed Forces
• Woi language, a Malayo-Polynesian language
• Women's Organization of Iran, an Iranian women's rights organization

• Athletics at the 1991 Pan American Games – Men's 10,000 metres
• Athletics at the 1991 Pan American Games – Men's 100 metres
• Athletics at the 1991 Pan American Games – Men's 1500 metres
• Athletics at the 1991 Pan American Games – Men's 200 metres
• Athletics at the 1991 Pan American Games – Men's 400 metres
• Athletics at the 1991 Pan American Games – Men's 5000 metres
• Athletics at the 1991 Pan American Games – Men's 800 metres
• Athletics at the 1991 Pan American Games – Men's decathlon
• Athletics at the 1991 Pan American Games – Men's discus throw
• Athletics at the 1991 Pan American Games – Men's hammer throw
• Athletics at the 1991 Pan American Games – Men's high jump
• Athletics at the 1991 Pan American Games – Men's javelin throw
• Athletics at the 1991 Pan American Games – Men's long jump
• Athletics at the 1991 Pan American Games – Men's marathon
• Athletics at the 1991 Pan American Games – Men's pole vault
• Athletics at the 1991 Pan American Games – Men's shot put
• Athletics at the 1991 Pan American Games – Men's triple jump
• Athletics at the 1991 Pan American Games – Women's 10,000 metres
• Athletics at the 1991 Pan American Games – Women's 100 metres
• Athletics at the 1991 Pan American Games – Women's 1500 metres
• Athletics at the 1991 Pan American Games – Women's 200 metres
• Athletics at the 1991 Pan American Games – Women's 3000 metres
• Athletics at the 1991 Pan American Games – Women's 400 metres
• Athletics at the 1991 Pan American Games – Women's 800 metres
• Athletics at the 1991 Pan American Games – Women's discus throw