Juan Luis Sanfuentes Andonaegui (December 27, 1858 - July 16, 1930) was President of Chile between 1915 and 1920.
Sanfuentes was the son of writer and politician Salvador Sanfuentes Torres and Matilde Andonaegui. Orphaned at an early age and raised by his older brother, Enrique Salvador Sanfuentes, he trained as a lawyer at the University of Chile. He graduated with a Doctor of Law in 1879. He married Ana Echazarreta (ca. 1865 - 1927) in 1885, and the couple would have five children.
Rising to the position of Minister of Finance under Federico Errazuriz Echaurren in 1901, Sanfuentes served as President of the Senate of Chile from 1906 through 1909.
The Chilean presidential election of 1915 developed into a bitterly contest between Sanfuentes —a coalition candidate of the Liberal Democratic Party and the Conservative Party— and Javier Angel Figueroa —supported by the Liberal Alliance parties. Sanfuentes beat Figueroa by a single vote, among allegations of fraud and electoral intervention. The National Congress was called to confirm the result.
Through World War I Chile remained neutral. While the conflict lasted, domestic industry had one of its biggest booms, with the national industry growing 53% in those four years. But the end of the war led to a crisis of the nitrate industry, which resulted in a wave of social unrest. Sanfuentes' hard line against striking coal miners and trade unionists in the final year of his presidency was a key factor in the rise of his liberal reformer successor.
After office Sanfuentes retired from public life, devoting himself to family life with his wife in his estate, Camarico.