George Miller O'Brien (June 17, 1917 – July 17, 1986) was a Republican member of the United States House of Representatives.

During the war, O'Brien rose to the rank of lieutenant colonel while fighting in Germany.

In 1970, he was appointed to the state's Legislative Advisory Committee, and in 1971 he was elected to the Illinois House of Representatives.

In April 1986, O'Brien discovered that he had prostate cancer, which forced him to give up his bid for an eighth term.

Fellow Illinois Republican Congressman John E. Grotberg too died of cancer just four months later.