USS O'Brien (Destroyer No. 51/DD-51) was the lead ship of her class of destroyers built for the United States Navy prior to the American entry into World War I. The ship was the second US Navy vessel named in honor of Jeremiah O'Brien and his five brothers Gideon, John, William, Dennis, and Joseph who, together on the sloop Unity, captured a British warship during the American Revolutionary War. O'Brien was laid down by William Cramp and Sons of Philadelphia in September 1913 and launched in July 1914.