Greg Allen may refer to:

• Greg Allen (rugby league) (1947–2009), Australian rugby league player
• Greg Allen (baseball) (born 1993), American Major League Baseball outfielder
• Greg Allen (American football) (born 1963)
• Greg Allen (footballer) (born 1967), English midfielder footballer

• No, Not Me, Never
• Nonotuck Mountain
• Non, ou a Va Gloria de Mandar
• "Non", ou A Vã Glória de Mandar
• Non, ou A Vã Glória de Mandar
• Non, ou a Vã Glória de Mandar
• Non-Overlapping Magisteria
• Non Overlapping Magisteria
• Non-overlapping magisteria
• Nonoy Aquino
• Nonoy Baclao
• Nonoy Marcelo
• Nonoy marcelo
• Nonpaired
• Nonpaired test
• Nonpala
• Non-Pama–Nyungan
• Non-pan shabu shabu
• Non-paper
• Nonpaper
• Nonparametric analysis
• Nonparametric estimator
• Nonparametric inference
• Non-parametric statistical tests
• "Nonpareil" Dempsey