Daniel Duncan

• Daniel Duncan (physician), Scottish-French doctor and chemist
• Daniel Duncan (Ohio politician), congressman from the US state of Ohio
• Daniel Duncan McKenzie, parliamentarian and jurist from the Canadian province of Nova Scotia
• Daniel Kablan Duncan, foreign minister of Côte d'Ivoire
• Dan Duncan, American co-founder, chairman and majority shareholder of Enterprise Products
• Danny Duncan (musician), musician with We the Kings