Grant Simmer (born 1957) is an Australian sailor and yacht designer who has competed in multiple America's Cups. He sailed as navigator on Australia II when it won the 1983 America's Cup. He stayed with Alan Bond's syndicate and was navigator on Australia IV during the 1987 Defender Selection Series. He was a co-owner of North Sails Australia for 17 years until, in 2000, Simmer joined Alinghi as managing director and head of design. He helped design their winning 2003 and 2007 America's Cup boats as well as Alinghi 5 for the 2010 America's Cup defence.