Nathan Phillip Cohen MNZM (born 2 January 1986) is a New Zealand rower. He is a two-time world champion, and won a gold medal in the Olympics. In 2006, rowing a single scull, he won a gold medal at the World University Games. In doing so, he became the first New Zealander to win a gold medal at the World University Games in any sport. Cohen and his rowing partner, Joseph Sullivan, won back-to-back gold medals in the men's double sculls at both the 2010 and 2011 World Rowing Championships. At the 2012 Summer Olympics, he and his partner won the gold medal in the men's double sculls, after breaking the Olympic best time in the heats. In 2013, Cohen was made a Member of the New Zealand Order of Merit for his services to rowing.

Cohen was born in Christchurch, in the South Island of New Zealand. His father is Phil Cohen. His younger brother Hayden, exactly six years his junior, is also a rower. Hayden was the 2012 U23 World Champion in the double scull, and in 2013 partnered with Nathan in the quad scull, winning a silver medal in the first World Cup regatta held in Sydney.

Cohen grew up in Invercargill in Southland, and started rowing in 2000. He grew up racing on Lake Ruataniwha in Twizel, in the South Island of New Zealand.

Cohen won the boys under-18 single scull event at the New Zealand Secondary School Rowing Championships in 2003, while attending James Hargest High School. He credits that with being his most memorable race, saying: "It showed me that if you wanted something enough and were willing to push yourself beyond all your perceived limits, anything was possible."

After graduating high school, he began studying for an engineering degree at the University of Canterbury. He later switched to studying for a commerce degree at Massey University, by correspondence. He attended the University of Otago, where he was a member of the Otago University Rowing Club. He is a member of the Invercargill Rowing Club, which honored him for his accomplishments by making him a life member.

In both 2003 and 2004, Cohen was second in the World Rowing Junior Championships in the single scull. In 2005, he won a silver medal in the World Rowing U23 Championships.

In the summer of 2006, rowing single sculls Cohen won a silver medal at the World Rowing U23 Championships in Belgium, a gold medal in the Commonwealth Rowing Regatta in Scotland, and a gold medal at the World University Games by 8 seconds in Lithuania. He became the first New Zealander to win a gold medal at the World University Championship in any sport. In recognition of his accomplishment, Cohen was awarded an Outstanding Achievement Award at the NZ Universities Blues Awards.

In 2007, Cohen won a silver medal at the United States World Rowing Challenge in Oklahoma in men's single sculls. In 2007 and early 2008, he rowed with Matthew Trott in the World Rowing Championships in Munich, coming in sixth in the double sculls and securing a berth for New Zealand at the Olympics the following year.