Truxtun Beale (March 6, 1856 – June 2, 1936) was an American diplomat.
Beale was born in San Francisco to Edward Fitzgerald Beale and Mary Engle Edwards; his siblings were Mary (1852–1925), who married Russian diplomat George Bakhmeteff, and Emily (1854–1912), who married John Roll McLean. He was named for his grandfather Commodore Thomas Truxtun. In 1874 he graduated from the Pennsylvania Military College, and four years later, after studying law at Columbia University, was admitted to the bar. From 1876 to 1877 Beale was secretary to his father the US Ambassador to Austria-Hungary in Vienna. Instead of practicing law, he became manager of his father's Tejon Ranch in California, where he remained for 13 years.
In 1891 he was appointed by President Harrison United States Minister to Persia, and a year later, Minister (afterward Envoy Extraordinary and Minister Plenipotentiary) to Greece, Romania, and Serbia, making him ambassador to three countries at once. The years 1894-96 he devoted to travel in Siberia, Central Asia, and Chinese Turkestan. Many articles on international questions were contributed by him to reviews and magazines.
Upon the death of Edward Beale in 1893, Truxtun Beale inherited the Tejon Ranch. By his first wife, Harriet Blaine of Maine (the daughter of James G. Blaine), whom he married in 1894, he had a son, Walker Blaine Beale (1896 - September 18, 1918), a Lieutenant in the United States Army killed in action in France in World War I.