It is the third jab authorised for use in the country, joining vaccines made by Pfizer and AstraZeneca.
The UK Government has ordered 17 million doses of the Moderna jab, but supplies will not delivered until the spring.
Health Secretary Matt Hancock said: “This is further great news and another weapon in our arsenal to tame this awful disease.
“We have already vaccinated nearly 1.5 million people across the UK and Moderna’s vaccine will allow us to accelerate our vaccination programme even further once doses become available from the spring.
“While we immunise those most at risk from Covid, I urge everyone to continue following the rules to keep cases low to protect our loved ones.”
Prime Minister Boris Johnson tweeted it was “excellent news” the Moderna vaccine had been approved for use.
He said: “Our national vaccine effort is accelerating to vaccinate priority groups with our existing two vaccines, and the Moderna doses will add to that when they become available in spring.”
