Morgan, Grenfell & Co. was a leading London-based investment bank regarded as one of the oldest and once most influential British merchant banks. It had its origins in a merchant banking business commenced by George Peabody. Junius Spencer Morgan became a partner in 1854. After Peabody retired the business was styled J. S. Morgan & Co. In 1910, it was reconstituted as Morgan Grenfell & Co. in recognition of the senior London-based partner, Edward Grenfell, although J. P. Morgan & Co. still held a controlling interest. In the 1930s, it became a commercial bank and the Morgan family relinquished their controlling interest in the business. After a period of retrenchment, it expanded under the management of second Viscount Harcourt in the 1960s. The link with J. P. Morgan & Co. ended completely in the 1980s. The business also became embroiled in the Guinness share-trading fraud at that time. In 1990, Morgan Grenfell was acquired in an agreed deal by its minority shareholder, Deutsche Bank. The use of the Morgan Grenfell name was discontinued by Deutsche Bank in 1999.

George Peabody was an American financier and philanthropist. He is often considered the father of modern philanthropy.