Robert Charles Mardian (October 23, 1923 – July 17, 2006) was a United States Republican party official who served in the administration of Richard Nixon, and was embroiled in the Watergate scandal as one of the Watergate Seven who were indicted by a grand jury for campaign violations. His conviction for conspiracy was overturned because of procedural unfairness and he was not subsequently retried.

Mardian's father, Samuel, was from the Armenian town of Hadjin in the Vilayet of Adana in the Ottoman Empire (present day Saimbeyli in Mediterranean Turkey). He was born Samuel Zeligian into a Christian family and was a member of Second Congregational Church in Hadjin. Following the massacre of 35,000 Armenians in Adana in 1909 and the siege of Christian Hadjin Samuel moved his family and was in the United States by 1912. Samuel settled in California and supported progressive politicians such as Hiram Johnson and Franklin D. Roosevelt.

Samuel Mardian's four sons, however, adopted free-market politics. Robert Mardian's brother, Daniel Mardian Sr. founded Mardian Construction Company, a multi-million dollar concern, which contributed to Arizona's prominence and Samuel Mardian Jr. joined him as the vice president. Samuel Mardian also served as mayor of Phoenix, Arizona from 1960 to 1964, and was a leading supporter of Barry Goldwater.

Robert Mardian went to public school in Pasadena, California followed by Columbia University, North Dakota State Teachers College, and the University of California, Los Angeles. While serving in the United States Navy he met and married Dorothy Denniss in 1946. They had three sons. Mardian was awarded a law degree from the University of Southern California in 1949. After leaving law school he went into private practice as a corporate lawyer.

In 1956, Mardian, already active in the Republican Party, was appointed to a vacant seat on the Pasadena School Board. He was elected in 1957 but resigned shortly afterwards through pressure of work. From 1962, Mardian left his law practice to become vice president and chief legal officer of a savings and loan association. In the 1964 presidential election he managed the Goldwater campaign in four western states; although Goldwater was unsuccessful, his campaigning ability impressed Richard Nixon and he was appointed to the same position in Nixon's 1968 campaign. This time, of the four western states, the Republicans carried all but Washington. In the intervening years, he served as chairman of Ronald Reagan's state advisory committee during his 1966 gubernatorial campaign in California.