Gerard Nijboer (born 18 August1955 in Hasselt) was a Dutch athlete who competed mainly in the Marathon.
He competed for the Netherlands in three consecutive Summer Olympics, starting in 1980 (Moscow, Soviet Union), when he won the silver medal in the Men's Marathon. He became European champion in the marathon in 1982, for which he was named Dutch Sportsman of the year at the end of the year.
His personal best time was 2:09:01 at the Amsterdam Marathon of April 26, 1980, which was at the time the second best marathon ever (after Derek Clayton's 2:08:34 run in 1969).