Sixty-eight per cent of KPMG's 11,000 staff took part in a vote to select the firm's next charity of the year, with Barnardo's emerging as the winner.
KPMG's previous two-year partnership with the Alzheimer's Society, which came to an end on 30 September, raised £1.06m.
Alison Halsey, lead charity relationship partner at KPMG, said: "We are very excited to be partnering with Barnardo's, which represents such a fantastic cause.
"Children are everybody's future and I am sure that staff at KPMG will be extremely motivated to raise as much money as they can."
Martin Narey, chief executive of Barnardo's, said: "I hope we can inspire along the way, with our work with more than 100,000 of the most vulnerable children in the UK, to raise a record amount."