Arnulfo Arias Madrid (15 August 1901 – 10 August 1988) was a Panamanian politician, medical doctor, and writer who served as the President of Panama from 1940 to 1941, again from 1949 to 1951, and finally for 11 days in October 1968.

Throughout his adult life, he warned about the increasing influence of the military in Panamanian politics and vowed to reduce that. In turn, he was denied his presidential electoral success in 1948 by the military. Arias's tenure as president was characterized by corruption, nepotism and autocratic practices. In 1951, Arias sought to restore the 1941 constitution and threatened to disband the Panama legislature, which prompted protests. The legislature impeached Arias, who was succeeded by Alcibiades Arosemena.

He was removed from the presidency thrice by the military.