In 1966, a coal waste tip slid down a mountain above Aberfan, south Wales, onto the village school, killing 116 children and 28 adults.
The Green Hollow has been written by author Owen Sheers based on interviews with those involved.
The drama is part of a new season of BBC Wales-produced programming.
The hour-long programme, in the form of a poetry film, will feature high-profile Welsh actors including Michael Sheen, Jonathan Pryce, Sian Phillips and Eve Myles.
Owen Sheers said of the programme: "As well as remembering the circumstances and consequences of the disaster, it became equally important for me to create a portrait of what the village was like in 1966 before tip number seven collapsed on Pantglas School - a thriving, vibrant cultural and economic community - and also to paint a picture of the fortitude and optimism present in the village today."
The programme will be broadcast on the day of the anniversary, Friday 21 October on BBC One Wales and BBC Four.
Also making a return to both channels in October will be Ordinary Lies, the Newport-based drama set in a sports company starring Griff Rhys Jones and Kimberley Nixon.
A Doctor Who spin-off for young adults, Class, will be screened on BBC Three from 22 October, while the Ceredigion-set crime drama Hinterland, which is in its third series, will return in the new year to BBC One Wales and BBC Four starring Richard Harrington.
BBC Wales director Rhodri Talfan Davies said: "These four very special shows provide a glimpse into very different Welsh experiences - from the lives and passions of a Newport workforce to the brooding landscapes of west Wales.
"They showcase the brilliant production and acting talent Wales has to offer, and underline the BBC's commitment to improve the portrayal of Wales on the BBC's networks."

The group, who have sold 70 million records, said Mr Corbyn had inspired young people and offered a "believable" alternative to business as usual.
Mr Corbyn has been backed by several stars, such as actor Daniel Radcliffe.
But best-selling Harry Potter author JK Rowling has called him a lousy leader.
Mr Corbyn is being challenged for the leadership by Owen Smith. The result of the election will be announced on 24 September.
The Labour leader, who has said he wants the arts to be a priority for the next Labour government, has received a number of celebrity endorsements in recent weeks.
Birmingham-based UB40, named after the then government's unemployment benefit form, were one of the most successful British groups of the 1980s and 1990s, notching up 50 hit singles - among them the chart toppers Red Red Wine, Can't Help Falling in Love and I Got You Babe.
Although three members of the original line-up have left in recent years, sparking a legal dispute over the use of the band's name, the remaining members led by guitarist and vocalist Robin Campbell have endorsed Mr Corbyn.
"Jeremy has re-ignited an interest in politics for people who no longer felt included, and engaged and inspired a new generation of young voters who, for the first time, believe that they have an incorruptible politician who truly represents them," Mr Campbell said.
Drummer Jimmy Brown said Mr Corbyn was the only frontline politician "willing to speak up for working people who have been badly treated by successive governments, including New Labour, in recent decades".
Mr Corbyn, who is opposed by the majority of his MPs and lost a vote of no confidence after the EU referendum, welcomed the band's backing ahead of a planned joint appearance on Tuesday.
"UB40's story was and remains inspiring; people from across cultures and backgrounds coming together and combining their talents - in a time when prejudice was more prevalent - and creativity to produce music that has endured across decades," he said.
As part of his arts manifesto released last month, Mr Corbyn pledged that all primary schools in England would get extra cash to fund arts activities and a single national scheme for arts scholarships would be set up.
The Labour leader told the Guardian on Monday he would be happy to meet JK Rowling to discuss their differences after she said he was taking the party in the wrong decision.
Her suggestion that Mr Corbyn risked destroying Labour and that the poorest in society need an "electable" alternative to the Conservatives not "mouthy, impotent socialism" provoked an angry response from Corbyn backers on social media.

No new date has yet been set for the game to be played.
A drama portraying the events surrounding the deaths of 144 people in a Welsh village will be aired to mark the 50th anniversary of the tragedy.
[NEXT_CONCEPT]
British reggae band UB40 have praised Jeremy Corbyn as an "incorruptible politician" who will put working people first as they backed his campaign to remain as Labour leader.
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Saturday's Women's Super League 1 game between Doncaster Rovers Belles and Arsenal Ladies has been postponed because of a waterlogged pitch.