Sir John William Lubbock, 3rd Baronet (March 26, 1803–June 21, 1865) was an English banker, mathematician and astronomer.
He was born in Westminster, the son of Sir John William Lubbock, of the Lubbock & Co bank. He was educated at Eton and then Trinity College, Cambridge, graduating in 1825. He immediately joined his father’s bank.
In 1828 he joined the Royal Astronomical Society, in 1829 he joined the Society for the Diffusion of Useful Knowledge and became a member of the Royal Society. He was twice Treasurer (1830-35, 1838-45) and three times Vice-President (1830-35, 1836-37, 1838-46) of the Royal Society. For his studies of tides he was awarded the Royal Medal in 1834.
Lubbock was the first Vice-Chancellor of the University of London (1837-42), a position later held by his eldest son, Sir John Lubbock, 4th Bt, who was later created Baron Avebury in 1900.
Lubbock became head of Lubbock & Co, retired mostly in 1840, but oversaw the merger that created Roberts, Lubbock & Co in 1860.
He married Harriet Hotham in 1833 and they had eleven children.