Relatives of the eight people who lost their lives have chosen to maintain a dignified silence over the years, but their loved ones have not been forgotten.
From the first members of the emergency services on the scene, to the local Catholic curate at the time - they all recall the horror of that night, Saturday 30 October.
"We were just stunned by what we saw. It just seemed like there were bodies everywhere," paramedic Adrian McAuley tells UTV's Gareth Wilkinson.
Ex-RUC officer Norman Hamill remembers the sight of the dead and dying, some of whom he knew.
"It was an absolutely ghastly sight. People in the bar were in desperate shock," he says.
There were dead and dying on the floor of the bar - some of whom I knew.
Norman Hamill, ex-RUC
What had been an evening to celebrate Halloween turned into a nightmare, when the gunmen burst into the pub shouting: "Trick or treat!"
They opened fire, with an AK-47 assault rifle and a 9mm pistol, killing and wounding indiscriminately.
The youngest of the victims was Karen Thompson, aged just 19 and from Limavady. She had been enjoying the evening with her boyfriend, 20-year-old Greysteel man Steven Mullan.
It is thought that Karen remonstrated with the gunmen, thinking at first that it was a prank and telling them it wasn't funny. Both she and Steven were shot dead.
The only other woman to be killed was 59-year-old Moira Duddy, a married mother-of-six. Her husband escaped injury.
The oldest of the victims, and indeed one of the oldest people to die during the Troubles in Northern Ireland, was 81-year-old James Moore.
His son owned the Rising Sun and the married father-of-five had been ordering a drink at the bar when the shooting started. He was fired at multiple times, with four bullets hitting him.
John Moyne, 50, died protecting his wife - he only had time to throw her to the floor and shield her before he was shot.
Joseph McDermott, 60, was also killed in the gun attack. He was single and without children, living alone at his Greysteel home, but was a well-known character in the village.
John Alexander Burns, 54 and a father-of-three from Eglinton, was shot in the stomach by one of the gunmen. The former UDR man died from his injuries, while his wife was badly wounded.
Nearly six months after the attack, an eighth victim - 76-year-old former B Special Victor Montgomery - collapsed and died as a direct result of injuries sustained in the shooting.
Greysteel will always be remembered as one of the darkest chapters of the Troubles but, within a year, the first IRA and loyalist ceasefires were called.
Gareth Wilkinson, UTV
In the wake of the massacre, the UFF claimed that the shooting had been a revenge attack after nine Protestant people were killed in an IRA bomb on the Shankill in west Belfast a week earlier.
The families of those killed in the blast had appealed for no retaliation.
"This is the continuation of our threats against the nationalist electorate that they would pay a heavy price for last Saturday's slaughter of nine Protestants," the UFF statement said.
Of the eight people killed in Greysteel, two were actually Protestants while another came from a mixed background.
In the week that followed the Shankill bomb, six other people - all Catholics - were also targeted and killed by loyalist paramilitaries before the Greysteel shooting was carried out.
As those who lost their lives were laid to rest, then SDLP leader John Hume wept amid fears that Northern Ireland was heading back into the darkest days of the Troubles.
In just one week, 23 innocent people had been brutally murdered - the highest death toll in any month since 1976.
But out of grief on both sides of the community came a renewed desire to push forward in the bid for peace which was to ultimately herald the end of the Troubles.
In the bid to hunt those responsible for Greysteel, the decision was taken to show the public the true horror of the scene via the media.
Chilling images were broadcast of the blood-soaked bar riddled with bullet holes.
Unless we get a total cessation of violence, then this sort of madness is going to continue.
SDLP leader John Hume, speaking in 1993
It emerged that 45 shots had been fired in total and 19 people had been shot, eight of them fatally wounded. The gunman armed with the AK-47 had even paused to reload.
But they were soon caught.
Stephen Irwin had been the one to empty the clip of the assault rifle and then reload in order to keep firing, all after shouting: "Trick or treat!"
Geoffrey Deeney had been the one to curse when his pistol jammed after just one shot.
And it was Torrens Knight who had been the getaway driver and who would - within days - become the face of sectarian hatred, snarling abuse at the victims' relatives as he left court charged with the killings.
All three were convicted, but released early under the terms of the Good Friday Agreement in 2000.
Irwin was returned to prison to finish his sentence when he was convicted in 2005 over a knife attack, while Knight was jailed again in 2009 for an attack on two women in a Coleraine bar.
He was released in 2010.
In the 20 years that have passed since the Greysteel atrocity, the small village community remains united. The families have kept their silence, never mounting campaigns for truth or public enquiries.
The Rising Sun is still open for business, bearing a memorial outside to those who lost their lives.
May their sacrifice be our path to peace.