Standing trial for his alleged role in the September 11 attacks on the United States, Moussaoui's request for testimony from two other suspects was granted on Friday by District Judge, Leonie Brinkema.
Moussaoui had requested testimony from Khalid Shaikh Mohammed, the alleged mastermind behind the attacks, and Mustafa Ahmed al-Hawsawi, who allegely funneled money to the September 11 hijackers.
Moussaoui says the two men would testify that he had nothing to do with the attacks.
A French citizen, Moussaoui, 35, is the only person charged in the United States for the attacks.
Khalid Shaikh Mohammed and Mustafa Ahmed al-Hawsawi were arrested by Pakistani and FBI agents in March from an alleged al-Qaida safe house in Pakistan.
They are being held by the US at undisclosed destinations.
The judge's approval came amid a legal dispute over Moussaoui's access to another al-Qaida member, Ramzi Binalshibh.
Despite a court ruling clearing the way for Moussaoui to question Binalshibh, the US government is refusing to let the questioning go ahead on the grounds of national security.