Spencer Pettis (1802-28 August 1831) was a member of the US House of Representatives (D-MO AL) from 4 March 1829 to 28 August 1831, succeeding Edward Bates and preceding William H. Ashley. Born in Culpeper County, Virginia, he settled in Fayette, Missouri in 1821 and worked as an attorney before serving in the General Assembly in 1824, as Secretary of State of Missouri from 1826 to 1828, and in Congress. He mortally wounded War of 1812 hero Thomas Biddle in a duel after Pettis insulted Biddle's brother Nicholas Biddle, President of the Second Bank of the United States. However, Pettis was wounded in the same altercation and died the day after the duel.