Lammot du Pont II (October 12, 1880 – June 24, 1952) was an American businessman who was the head of the du Pont family's E. I. du Pont de Nemours and Company for 22 years.
He was born on October 12, 1880 in Wilmington, Delaware. He was the ninth of the eleven children of Lammot du Pont and his wife, Mary Belin.
Married four times, Lammot du Pont's first wife was Natalie Driver, sister of Rodgers Wilson. They married on January 27, 1903.
On March 15, 1926, Lammot du Pont was elected President of E.I. du Pont de Nemours Co., succeeding Irénée du Pont, who was elected Chairman of the Board of Directors.  Lammot du Pont remained President until May 20, 1940 when he was succeeded by Walter S. Carpenter, Jr. At the same time, Lammot replaced his brother Pierre S. du Pont as Chairman of the Board. 
He died on June 24, 1952 in New London, Connecticut of heart disease at age 71.
His son, David F. du Pont, by his fourth wife, died at age twenty-one as a result of an automobile accident at Fishers Island, New York October 3, 1955.