Jonathan Mason (September 12, 1756-November 1, 1831) was a Federalist United States Senator and Representative from Massachusetts during the early years of the United States.
Mason was born in Suffolk County, Massachusetts. He attended Boston Latin School the College of New Jersey (now Princeton University), graduating in 1774. After studying law and being admitted to the bar in 1779, he was a Member of the Massachusetts House of Representatives from 1786 to 1796. From 1797 to 1798, he served with the Massachusetts Governor's Council and was elected to the for the following two years, and was in the Massachusetts Senate from 1799 to 1800. Following the resignation of Senator Benjamin Goodhue, he was elected to the U.S. Senate, where he served from November 14, 1800 to March 3, 1803. He then resumed his law practice and served again in the Massachusetts Senate from 1803 to 1804 and the Massachusetts House from 1805-08. He served again in the US House of Representatives from March 4, 1817, to May 15, 1820, whereupon he resigned to pursue his law practice. He is interred in Mount Auburn Cemetery in Cambridge, Massachusetts.