Oscar William Gillespie (June 20, 1858 – August 23, 1927) was a U.S. Representative for the state of Texas.

Born near Quitman, Mississippi, Gillespie attended private schools and graduated from Mansfield college, Texas, in 1885.

He was admitted to the bar in 1886 and commenced his law practice in Fort Worth, Texas.

In 1902, the Democrats were unable to decide among three candidates for nomination to Texas's 12th Congressional District.

Gillespie and his main opponent, Judge Lee Riddle, put their names in a hat, drew one out and the loser agreed to withdraw and support the winner.