John McKinley (May 1 1780-July 19 1852) was a U.S. senator from the state of Alabama and an associate justice of the United States Supreme Court.

Born in Culpepper County, Virginia , his family moved to Kentucky when he was an infant. In that state he studied law and was admitted to the bar in 1800, practicing in Frankfort and Louisville before moving to Hunstville, Alabama .

After serving in the lower house of the Alabama state legislature, he was elected to the U.S. Senate, serving his first term from November 27, 1826 to March 3, 1831, being elected to fill out the rest of the term of Henry H. Chambers. Israel Pickens served as interim senator until McKinley was elected. He was reelected to the senate, but served only from March 4 1837 to his resignation to join the Court on April 22 of that year. There was no interim senator this time, and Clement C. Clay was elected to the post.

He made little contribution to the Court. In fifteen years there, he wrote only twenty-two opinions, and was noted for his commitment to state's rights.

|- style="text-align: center;" | width="30%" |Preceded by:
Gabriel Moore | width="40%" style="text-align: center;" |United States Senator from Alabama
1837 | width="30%" |Succeeded by:
Clement C. Clay

|- style="text-align: center;" | width="30%" |Preceded by:
(none) | width="40%" style="text-align: center;" |Associate Justice of the Supreme Court of the United States
January 9, 1838 – July 19, 1852 | width="30%" |Succeeded by:
John Archibald Campbell