Federalist Party, in United States history, the group that supported a strong central government during the administrations of George Washington and John Adams. The Federalists were the conservative party, led by Alexander Hamilton and Adams. They were opposed by the Republicans under Thomas Jefferson. Hamilton and Adams represented the group that had brought about adoption of the federal Constitution, and that championed the interests of business and industry.

The Federalists lost the Presidency to Jefferson in 1801 and thereafter declined steadily in influence, although they remained strong in New England. Federalist opposition to the War of 1812 and the secessionist proposals of the Hartford Convention discredited the party. Although the party broke up after 1816, some elected officials retained the Federalist label. The Whigs, Free Soilers, and Republicans adopted many Federalist principles.