Rasmus Nielsen may refer to:

• Rasmus Nielsen (footballer) (born 1987), Danish footballer
• Rasmus Nielsen (volleyballer) (born 1994), Danish volleyballer
• Rasmus Nielsen (ice hockey) (born 1990), Danish ice hockey player
• Rasmus Nielsen (squash player) (born 1983), Danish squash player
• Rasmus Nielsen (philosopher) (1809–1884), Danish philosopher and professor
• Rasmus Nielsen (biologist) (born 1970), professor of integrative biology at UC Berkeley
• Rasmus Kleis Nielsen, professor of political communication

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