Robert Nicols Martin (January 14, 1798 – July 20, 1870) was an American politician from Maryland.
Martin was born in Cambridge, Maryland, where he attended the public schools.
After his term, Martin settled in Baltimore and resumed the practice of law.
He was appointed by Governor Thomas Pratt as judge of the Maryland Court of Appeals and as chief justice of the western judicial district in 1845, in which capacity he served until the office was vacated by the Maryland Constitution of 1851.
He died at Saratoga Springs, New York, and is interred in the Christ Protestant Episcopal Church Cemetery in Cambridge.