The Civil Rights Act of 1964 (Pub. L. 88–352, 78 Stat. 241, enacted July 2, 1964) is a landmark civil rights and labor law in the United States that outlaws discrimination based on race, color, religion, sex, and national origin. It prohibits unequal application of voter registration requirements, racial segregation in schools and public accommodations, and employment discrimination. The act "remains one of the most significant legislative achievements in American history".

Initially, powers given to enforce the act were weak, but these were supplemented during later years. Congress asserted its authority to legislate under several different parts of the United States Constitution, principally its enumerated power to regulate interstate commerce under the Commerce Clause of Article I, Section 8, its duty to guarantee all citizens equal protection of the laws under the 14th Amendment, and its duty to protect voting rights under the 15th Amendment.

The legislation was proposed by President John F. Kennedy in June 1963, but it was opposed by filibuster in the Senate. After Kennedy was assassinated on November 22, 1963, President Lyndon B. Johnson pushed the bill forward. The United States House of Representatives passed the bill on February 10, 1964, and after a 72-day filibuster, it passed the United States Senate on June 19, 1964. The final vote was 290–130 in the House of Representatives and 73–27 in the Senate. After the House agreed to a subsequent Senate amendment, the Civil Rights Act of 1964 was signed into law by President Johnson at the White House on July 2, 1964.

In the 1883 landmark Civil Rights Cases, the United States Supreme Court had ruled that Congress did not have the power to prohibit discrimination in the private sector, thus stripping the Civil Rights Act of 1875 of much of its ability to protect civil rights.

In the late 19th and early 20th century, the legal justification for voiding the Civil Rights Act of 1875 was part of a larger trend by the United States Supreme Court majorities to invalidate most government regulations of the private sector, except when dealing with laws designed to protect traditional public morality.

In the 1930s, during the New Deal, the majority of the Supreme Court justices gradually shifted their legal theory to allow for greater government regulation of the private sector under the Commerce Clause, thus paving the way for the federal government to enact civil rights laws prohibiting both public and private sector discrimination on the basis of the commerce clause.

Influenced in part by the "Black Cabinet" advisors and the March on Washington Movement, just before the U.S. entered World War II, President Franklin Roosevelt issued Executive Order 8802, the first federal anti-discrimination order, and established the Fair Employment Practices Committee. Roosevelt's successor, President Harry Truman, appointed the President's Committee on Civil Rights, proposed the 20th century's first comprehensive Civil Rights Act, and issued Executive Order 9980 and Executive Order 9981, providing for fair employment and desegregation throughout the federal government and the armed forces.

The Civil Rights Act of 1957, signed by President Dwight D. Eisenhower on September 9, 1957, was the first federal civil rights legislation since the Civil Rights Act of 1875 to become law. After the Supreme Court ruled school segregation unconstitutional in 1954 in Brown v. Board of Education, Southern Democrats began a campaign of "massive resistance" against desegregation, and even the few moderate white leaders shifted to openly racist positions. Partly in an effort to defuse calls for more far-reaching reforms, Eisenhower proposed a civil rights bill to increase the protection of voting rights for African Americans.