Peter Nielsen

Peter Nielsen may refer to:

• Peter Nielsen (botanist) (1829-1897), Danish botanist, mycologist and plant pathologist
• Peter Nielsen (footballer) (born 1968), Danish footballer
• Peter Nielsen (sport shooter) (1890-1972), Danish Olympic shooter
• Peter Meinert Nielsen (born 1966), Danish road bicycle racer
• Peter Nielsen, air traffic controller at the time of the Überlingen mid-air collision
• Peter Nielsen, contestant on series four of The Apprentice (Irish TV series)