Robert Clymer Hendrickson (August 12, 1898 – December 7, 1964) was an American attorney, politician, and diplomat who served as a United States senator from New Jersey.

Born in Woodbury, New Jersey, Hendrickson attended public schools and during the First World War enlisted in the United States Army in 1918 and served overseas.

During the Second World War he rejoined the Army in 1943, was commissioned a major, served with the American Military Government in the Mediterranean Theater of Operations, and was subsequently promoted to lieutenant colonel in 1944, being separated from the service in 1946.

As a senior legal officer in the U.S. Army in North Africa, Italy, and Austria, he worked on the re-establishment of civil rights and local courts, the implementation of de-nazification programs, and the care of displaced persons.

President Dwight Eisenhower appointed Hendrickson to the post of United States ambassador to New Zealand, which he held from February 16, 1955, to November 20, 1956.