Citizens Bank parent Citizens Financial Group is laying off 900 employees, or 3 percent of its work force, across the bank's 13-state market.
The move affects workers in commercial lending, retail banking and global transaction services.
The bank, based in Providence, RI, employs about 24,500 overall.
A spokesperson said the move was necessary due to "reduced economic activity" but said no additional job cuts were planned.
Citizens is the Pittsburgh region's third largest bank by branches and fourth-largest by deposits.