Samuel Dexter (May 14, 1761–May 4, 1816) was an early American statesman who served both in Congress and in the Presidential Cabinet.

Born in Boston, he graduated from Harvard University in 1781 and then studied law at Worcester under Levi Lincoln, the future Attorney General of the United States. After he passed the bar in 1784, he began practicing in Lunenberg, Massachusetts . He was elected to the Massachusetts House of Representatives and served 1788 to 1790. He was elected to the 3rd Congress by way of the United States House of Representatives and then elected as Federalist to the United States Senate. In December 1999, he memorably wrote the memorial eulogy to George Washington upon the first president's death.

He served for less than a year as he was appointed United States Secretary of War by President John Adams in 1800. During his time at this station he urged congressional action to permit appointment and compensation of field officers for general staff duty. Upon Secretary of the Treasury Oliver Wolcott's resignation in December 1800, Adams appointed Dexter as interim Secretary. He then briefly conducted the affairs of the foreign Office and administered the oath of office to Chief Justice John Marshall and declined the ambassadorship to Spain.

He returned to Boston in 1805 and resumed practicing law. He left the Federalist party to espouse Republican views on the War of 1812, and he was an unsuccesful candidate for Governor of Massachusetts in 1814 and 1815. He was an ardent supporter of the temperance movement and presided over its first formal organization in Massachusetts. He died the same year and is buried in Mount Auburn Cemetery in Cambridge, Massachusetts.

|- style="text-align: center;" | width="30%" |Preceded by:
Oliver Wolcott, Jr. | width="40%" style="text-align: center;" |United States Secretary of the Treasury
1800–1801 | width="30%" |Succeeded by:
Albert Gallatin