U.S. District Judge Douglas Woodlock granted the three separate trials, scheduling the first for June and the others in September.
Azamat Tazhayakov and Dias Kadyrbayev, who attended the University of Massachusetts at Dartmouth with Tsarnaev, are charged with obstruction of justice and are being held without bail. And Robel Phillipos, a friend from Tsarnaev's teenage years in Cambridge who also went to UMass, is charged with lying to investigators and is out on bail.
Tazhayakov and Kadyrbayev allegedly removed a backpack and laptop from Tsarnaev's room at UMass after he became a suspect in the bombings.
Tsarnaev, 20, is awaiting trial on charges of setting off two bombs at the Marathon finish line on April 15, 2013. The bombings killed three people and injured scores more, including some who lost limbs.
Tamerlan Tsarnaev, 26, Dzhokhar's brother, was killed in a confrontation with police a few days later. The brothers allegedly killed a University of Massachusetts police officer while they were on the run.