Peggy Fortune said Loving, 68, died Friday at her home in rural Milford. She did not disclose the cause of death.
Loving and her white husband, Richard, changed history in 1967 when the U.S. Supreme Court upheld their right to marry. The ruling struck down laws banning racially mixed marriages in at least 17 states.
They had married in Washington in 1958, when she was 18. Returning to their Virginia hometown, they were arrested within weeks and convicted on charges of "cohabiting as man and wife, against the peace and dignity of the Commonwealth," according to their indictments.
The couple avoided a year in jail by agreeing to a sentence mandating that they immediately leave Virginia. They moved to Washington and launched a legal challenge a few years later.
After the Supreme Court ruled, the couple returned to Virginia, where they lived with their children Donald, Peggy and Sidney.
Richard Loving died in 1975 in a car accident that also injured his wife.
In a rare interview with The Associated Press last June, Loving said she wasn't trying to change history - she was just a girl who once fell in love with a boy.
"It wasn't my doing," Loving said. "It was God's work."