Harry Jacob Lemley (August 6, 1883 – March 5, 1965) was a United States federal judge.
Born in Upperville, Virginia, Lemley received an LL.B. from Washington and Lee University School of Law in 1910. He was in private practice in Hope, Arkansas from 1912 to 1939. He was a Member, Arkansas State Highway Audit Commission from 1931 to 1933.
On April 27, 1939, Lemley was nominated by President Franklin D. Roosevelt to a new joint seat on the United States District Courts for the Eastern District of Arkansas and the Western District of Arkansas created by 52 Stat. 584. He was confirmed by the United States Senate on May 8, 1939, and received his commission on May 11, 1939. He served as chief judge from 1948 to 1958, assuming senior status on September 5, 1958. Lemley served in that capacity until his death, in 1965.