The trial is scheduled to begin on June 5, 2028, 18 months later than the January 2027 start that prosecutors had requested.
The additional time is needed to resolve pre-trial disputes, including disagreements about what evidence can be presented at trial, Air Force Lieutenant Colonel Michael A. Schrama wrote in his ruling.
The US military and successive administrations have struggled for more than two decades to bring to justice the man charged with planning one of the deadliest attacks ever on the United States.
The 2028 trial depends on the case meeting deadlines and milestones along the way and it could again be delayed. A trial was previously scheduled in 2021 but later cancelled.
Mohammed is accused of developing and directing the plot to crash hijacked airliners into the World Trade Centre in New York and the Pentagon. Another of the hijacked planes flew into a field in Pennsylvania.
He faces trial alongside three alleged accomplices: Walid bin Attash, Ali Abdul Aziz Ali and Mustafa al-Hawsawi.
They are among the last of the detainees held at the US military base at Guantanamo Bay, Cuba.
A federal appeals court last year threw out an agreement that would have allowed Mohammed to plead guilty in a deal sparing him the risk of execution for al-Qaeda's 2001 attacks.
That deal stipulated life sentences without parole for Mohammed and two of his co-defendants. It also would have obligated the men to answer any lingering questions that families of the victims have about the attacks.
Afterfter negotiating the deal for two years, former US president Joe Biden's administration repudiated it.
15°C