Hamer v. Campell is a civil rights case which Fannie Lou Hamer brought against Cecil Campbell, the circuit clerk of Mississippi, for denying her and other Black people the right to register and vote.

Fannie Lou Hamer was a poor Black woman from the South who always questioned the unfair treatment and status of people of color in society.  Throughout her life, she constantly spoke out against Black oppression and organized rallies in support of desegregation.

In 1962, she joined SNCC, a group that used peaceful protests to end segregation in the South. She also attempted to pass the voter registration test, and as a result, was fired from her job and threatened with violence. In 1963, Hamer attempted to register for the third time and finally passed the test. Several months later, she was arrested in Winona, Mississippi, and brutally beaten by two prison inmates on orders from white police officers.

The Council of Federated Organizations (COFO) and its members supported the organizing of the Mississippi Freedom Democratic Party (MFDP) in 1964 so that Black people in Mississippi would have an alternative to the established Democratic Party, which excluded them. In the 1964 Mississippi primary, the MFDP got more votes than the established Democratic Party, but the national party would not seat MFDP delegates at its convention in Atlantic City, New Jersey.

The MFDP’s struggle and Fannie Lou Hamer's moving testimony about her beating won support all over the U.S. and was partly responsible for the passage of the Voting Rights Act of 1965. This act guaranteed federal protection of the right to vote and made it illegal to deny adult U.S. citizens this right.

After many setbacks, the Fifth Circuit Court of Appeals ruled that Hamer and others were discriminated against by being denied the right to register to vote. The elections were then overturned based on discriminatory election practices.