Mrs Williams lost her 15-year-old son Kevin at Hillsborough and worked tirelessly during the campaigners' fight for justice.
It was her fight to get her son's inquest verdict of accidental death overturned that is largely credited with securing fresh hearings for all of the 96 supporters who died on 15 April 1989.
She was diagnosed with terminal cancer in October but continued her campaign and attended a hearing at London's Royal Courts of Justice in December when the original inquest verdicts were quashed.
The Government has pledged that new hearings will be held as soon as possible, with a preliminary hearing scheduled for 25 April.
Despite the severity of her illness, she attended what was her last public appearance at the Hillsborough memorial service on Monday.
"Liverpool Football Club was today saddened to hear of the passing of long-time Hillsborough campaigner Anne Williams, who has lost her six-month battle with bowel cancer at the age of 62," read a statement on the club's official website.
"(She) summoned the strength to attend the 2013 Hillsborough Memorial Service at Anfield on Monday.
"It was an act so typical of a mum who simply refused to accept defeat.
"Anne may not have survived to see ultimate justice for her son but her actions have played a significant part in ensuring that 96 families have moved closer to Hillsborough closure."