James Neal scored one of the early goals and assisted on two others in the contest, which extended the Penguins' winning streak to nine games.
Pittsburgh pulled to within two points of the Atlantic Division leaders, the New York Rangers. Scoring star Sidney Crosby was a scratch despite being cleared to play again last week.
David Krejci scored both Boston goals in the second period. Marty Turco and Tim Thomas combined for 27 saves. The Bruins have lost four of their last six games but hold a 2-point lead in the Northeast Division.