Mr Musk made the announcement in the early hours of Sunday morning (UK times) after holding a poll that asked Twitter users to click “yes” or “no” on whether Mr Trump’s account should be restored.
The “yes” vote won, with 51.8 per cent.
“The people have spoken. Trump will be reinstated. Vox Populi, Vox Dei,” Musk tweeted, using a Latin phrase meaning “the voice of the people, the voice of God”.
It is not clear whether Mr Trump would actually return to Twitter.
An irrepressible tweeter before he was banned, the former president has said in the past that he would not rejoin the social media platform even if his account was reinstated.
Shortly after Mr Musk’s announcement on Twitter, the former president’s account reappeared on the social media platform.
While it still had over 1.2million followers, it was not following any other users.
Mr Trump’s last tweet was posted on January 9 2021, reading: “To all of those who have asked, I will not be going to the Inauguration on January 20th.”
All of his former tweets also reappeared when the account was reinstated – more than 59,000 of them.
Earlier in the evening while addressing a Republican Jewish group meeting in Las Vegas, Mr Trump said that he was aware of Mr Musk’s poll but that he saw “a lot of problems at Twitter”, according to Bloomberg.
“I hear we’re getting a big vote to also go back on Twitter. I don’t see it because I don’t see any reason for it,” the former president was quoted as saying.
“It may make it, it may not make it,” he added, apparently referring to Twitter’s recent internal upheavals.