Lillian Hardin Armstrong (née Hardin; February 3, 1898 – August 27, 1971) was an influential American jazz pianist, composer, arranger, singer, and bandleader. Born in Memphis, Tennessee, she grew up in a musically inclined household and was initially taught hymns, spirituals, and classical music on the piano. Her early education in music was furthered by her third-grade teacher and later at Mrs. Hook's School of Music. She attended Fisk University, where she received advanced training and earned a diploma before returning to Memphis in 1917.

In 1918, Hardin moved to Chicago, where she became a proficient sight-reader and worked as a sheet music demonstrator. Her career took a significant turn when she joined Lawrence Duhé's band and later King Oliver's Creole Jazz Band, where she met Louis Armstrong. She married Armstrong in 1924, and they collaborated on many recordings throughout the 1920s. Her compositions include notable pieces such as "Struttin' with Some Barbecue," "Don't Jive Me," and "Just for a Thrill," the latter becoming a hit when revived by Ray Charles in 1959.

Hardin Armstrong was inducted into the Memphis Music Hall of Fame in 2014, recognizing her contributions to jazz music. She passed away in Chicago, Illinois, on August 27, 1971, leaving behind a legacy as one of the most sought-after jazz pianists of her time.