George Peabody (/ˈpiːbɒdi/; February 18, 1795 – November 4, 1869) was an American financier and philanthropist. He is often considered the father of modern philanthropy.

Born into a poor family in Massachusetts, Peabody went into business in dry goods and later into banking. In 1837 he moved to London (which was then the capital of world finance) where he became the most noted American banker and helped to establish the young country's international credit. Having no son of his own to whom he could pass on his business, Peabody took on Junius Spencer Morgan as a partner in 1854 and their joint business would go on to become the global financial services firm J.P. Morgan & Co. after Peabody's 1864 retirement.

In his old age, Peabody won worldwide acclaim for his philanthropy. He founded the Peabody Trust in Britain and the Peabody Institute and George Peabody Library in Baltimore, and was responsible for many other charitable initiatives. For his generosity, he was awarded the Congressional Gold Medal and made a Freeman of the City of London, among many other honors.

Peabody was born in 1795 in what was then the South Parish of Danvers (now Peabody), Massachusetts. His family had Puritan ancestors in the state. As one of seven children in a poor family, George suffered some deprivations during his childhood, and was able to attend school for only a few years. When he was a teenager, his father died, and he worked in his brother's shop to support his widowed mother and six siblings. He later expressed "I have never forgotten and never can forget the great privations of my early years". These factors influenced his later devotion to both thrift and philanthropy.

In 1816, he moved to Baltimore, where he made his career and would live for the next 20 years. He established his residence and office in the old Henry Fite House, and became a businessman and financier.

At that time London, Amsterdam, Paris, and Frankfurt were at the center of international banking and finance. As all international transactions were settled in gold or gold certificates, a developing nation like the United States had to rely upon agents and merchant banks to raise capital through relationships with merchant banking houses in Europe. Only they held the quantity of reserves of capital necessary to extend long-term credit to a developing economy like that of the US.

Peabody first visited England in 1827, seeking to use his firm and his agency to sell American states' bond issues, to raise capital for those states' various programs of "internal improvements" (principally the transportation infrastructure, such as roads, railroads, docks and canals). Over the next decade Peabody made four more trans-Atlantic trips, starting in 1835 and establishing a branch office in Liverpool. Later he established the banking firm of George Peabody & Company (later stylised as J. S. Morgan & Co.) in London. In 1837, he took up permanent residence in London, where he lived for the rest of his life.

In the 1840s, the state of Maryland defaulted on its debt and Peabody, having marketed about half of Maryland's securities to individual investors in Europe, became persona non grata around London. The Times of London noted that while Peabody was an "American gentleman of the most unblemished character", the Reform Club had blackballed him for being a citizen of a country that reneged on its debts. At first, Peabody sent letters to scold Baltimore friends about the need for the state to resume interest payment and rewarded reporters with small gratuities for favourable articles about the state.