John Morris Sheppard (May 28, 1875 – April 9, 1941) was a Democratic United States congressman and United States senator from Texas. He authored the Eighteenth Amendment (prohibition) and introduced it in the Senate, and is referred to as "the father of national Prohibition."

Sheppard was born in Morris County in east Texas, the oldest of seven children, to lawyer John Levi Sheppard, later a judge and United States Representative; and his wife, the former Margaret Alice Eddins. Through his mother Margaret, Morris Sheppard was a direct descendant of Robert Morris (1734–1806) of Philadelphia, Pennsylvania, a financier who had signed the Declaration of Independence, the Articles of Confederation, and the United States Constitution.

Sheppard received his B.A. degree from the University of Texas at Austin in 1895, Phi Beta Kappa. While there, he was a member of Kappa Alpha Order. He received an LL.B. from the University of Texas School of Law in 1897. While in law school Sheppard became a member of the Methodist Church, and became friendly with two classmates, future Governor Pat Neff, and future U.S. Senator Tom Connally. In 1898, he received his LL.M. from Yale Law School.

He began practicing law with his father in Pittsburg, Texas and later Texarkana. In 1902, Morris Sheppard was elected as a Democrat to replace his deceased father in the United States House of Representatives. He held the seat until his resignation in 1913, when the Texas legislature elected him to the United States Senate. In 1914 and while holding the office of Senator, he was on the Central Committee of the First National Conference on Race Betterment, a conference on eugenics held at the Battle Creek Sanatorium. He served as Democratic whip between 1929 and 1933.

In the 1928 presidential election, Texas voters abandoned the Democratic candidate, Alfred E. Smith, Governor of New York and a Catholic, carrying the state for Republican Herbert Hoover and contributing to his victory. In the summer of 1929, First Lady Lou Hoover arranged the traditional teas for wives of congressmen, inviting Jessie De Priest, wife of Oscar Stanton De Priest of Chicago, the first African American elected to Congress in the 20th century. Senator Sheppard was among those who objected to this invitation, quoted as saying, "I regret the incident beyond measure. It is recognition of social equality between the white and black races and is fraught with infinite danger to our white civilization."

Sheppard held his Senate seat until his death in Washington, D.C. in 1941. Then-Representative Lyndon B. Johnson ran for Sheppard's Senate seat in the 1941 special election, and lost to Governor W. Lee O'Daniel.

As Senator, Sheppard sponsored progressive reform legislation promoting rural credit programs, child labor laws, and antitrust laws. He was also an advocate of women's suffrage in the United States. But he supported the maintenance in Texas and the South of racial segregation in public facilities and the disenfranchisement of blacks.

During his tenure, Sheppard was a vocal supporter of the temperance movement. He helped write the Webb–Kenyon Act (1913) to regulate the interstate shipment of alcoholic beverages, authored the Sheppard Bone-Dry Act (1916) to impose prohibition on the District of Columbia, introduced the Senate resolution for the Eighteenth Amendment establishing national prohibition, and helped write the Volstead Act that provided for its enforcement.