Jonathan George “Jonty” Farmer was a New Zealand sailor who competed in the Finn class. Farmer participated at the 1968 Mexico City Olympics with a best result of second place in the second race before finishing 11th overall after the seventh and final race. Four years later he travelled to the München Games as a reserve but did not compete. Farmer got another opportunity to sail at the Olympics at the 1976 Montréal Games, finishing 15th out of the 28 competitors. In the same year he finished second to Chris Law in the Finn Gold Cup in Brisbane.