Jay James O'Brien (February 22, 1883 – April 5, 1940) was an American bobsledder who competed in the late 1920s and early 1930s.
He won two medals at the Winter Olympics with a gold in the four-man event at Lake Placid, New York in 1932 and a silver in the five-man event at St.
Moritz in 1928.
At 48 years old, he was the oldest Olympic champion.
O'Brien was also a jockey, and was head of the United States Olympic Bobsled Committee at the time of the 1932 Winter Olympics in Lake Placid.