A US judge sentenced Azamat Tazhayakov, a student from an affluent family in Kazakhstan, to three-and-a-half years for obstruction and conspiracy.
He has already spent more than two years in custody.
In a separate hearing, Robel Phillipos, the son of an Ethiopian immigrant, was sentenced to three years for lying to the FBI.
Phillipos, who graduated high school with Tsarnaev in 2011, confessed at the end of a fifth interview with the FBI to watching a third friend remove evidence from the room.
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The April 15, 2013 bombings at the Boston Marathon were among the deadliest in the United States since the September 11 Al-Qaeda attacks in New York, and sowed terror throughout the city.
Shortly after the Federal Bureau of Investigation released images of the suspects to the public on April 18, Kadyrbayev and Tazhayakov went to Tsarnaev's dorm room to remove incriminating evidence.
They took a backpack, tossed it in the garbage and kept a laptop in what prosecutors said was an attempt to protect Tsarnaev while he was on the run.
The backpack contained fireworks allegedly used in bomb-making, a jar of petroleum jelly and a thumb drive.
It was recovered by the FBI two days later at a landfill site.