The US Food and Drug Administration granted an emergency use authorization for the vaccine, developed with German partner BioNTech, which was shown to be 95% effective in preventing the disease in a late-stage trial.
The FDA said the vaccine can be given to people aged 16 and older. Healthcare workers and elderly people in long-term care facilities are expected to be the main recipients of a first round of 2.9 million doses.
The US government has said it will begin distributing the vaccine around the country immediately after FDA authorization, and that the first inoculations would happen early next week.
Millions of Americans could begin getting vaccinated this month, especially if a second vaccine from Moderna Inc is quickly approved.
The Pfizer/BioNTech vaccine was first approved in Britain earlier this month, and UK residents began receiving the shots on Tuesday. Canada also authorized the vaccine and expects to start inoculations next week.