Gershom Mendes Seixas (1745–1816) was the first native-born Jewish minister in the United States. He was the minister of Congregation Shearith Israel, the Spanish and Portuguese Synagogue of New York City from 1768 to 1776 and again from 1784 to 1816. Although not an ordained Rabbi, he served as Hazzan and Minister to the Congregation and was among the first Jewish communal leaders who was born and educated in the United States. He was also the first American Jewish clergyman to give a sermon in English.
Seixas was an ardent patriot during the American Revolution. He moved the congregation to Philadelphia's Congregation Mikveh Israel and was the Hazzan there for the duration of the war.
In 1783, he successfully sought revisions in a constitutional clause newly adopted by the Pennsylvania State Legislature, which required a religious examination for seekers of public office.
Seixas was one of the fourteen recognized ministers in New York in 1789 who participated in George Washington's first inauguration at Federal Hall in New York City.
He delivered the first Thanksgiving address in an American synagogue following the adoption of the United States Constitution.
He was one of the most vigorous defenders of the much-maligned James Madison administration during the War of 1812.