John Louis Johnson (born John Louis Mercer; November 18, 1869 – January 28, 1941) was an American left-handed pitcher who played briefly for the Philadelphia Phillies during the 1894 season. Johnson was born in Pekin, Illinois.

In his major league career, Johnson posted a 1–1 record with a 6.06 ERA in four appearances, including three starts and two complete games, giving up 22 earned runs on 44 hits and 15 walks while striking out 10 in 32+2⁄3 innings of work.

Johnson died in Kansas City, Missouri at the age of 71.

• Career statistics from Baseball Reference, or Baseball Reference (Minors)