Twenty-five other people were injured in the crash, the emergency services ministry said in a statement. It did not state the severity of the injuries.
The accident occurred when the truck ploughed into the side of the bus near Oznobishino, a settlement in the Moscow municipality about 25 miles south of the city centre.
Russian news reports say the drivers of both vehicles are among those in hospital.
COMMENT RULES: Comments that are judged to be defamatory, abusive or in bad taste are not acceptable and contributors who consistently fall below certain criteria will be permanently blacklisted. The moderator will not enter into debate with individual contributors and the moderator’s decision is final. It is Belfast Telegraph policy to close comments on court cases, tribunals and active legal investigations. We may also close comments on articles which are being targeted for abuse. Problems with commenting? firstname.lastname@example.org