The poll - carried out by Euromoney Institutional Investor Plc - showed the German lender ranked top for the seventh year in a row, despite its market share dipping more than any other institute in the top 20.
Barclays surged ahead of UBS SG into second position, pushing the Swiss bank into third spot.
Nick Howard, head of foreign-exchange and emerging market distribution at Barclays, said: "We have a very clear goal of becoming the number one foreign-exchange bank globally. Our rise to second place provides confirmation that we are steadily improving."
HSBC ranked sixth in the list, while Royal Bank of Scotland dropped two places to seventh.
It recently emerged that Deutsche Bank is being sued by the US government, which alleged the lender recklessly chose mortgages to be included in a government insurance program.
By Asim Shah