The Apportionment Act of 1792 (1 Stat. 253) was the first Apportionment Act passed by the United States Congress on April 10, 1792, and signed into law by President George Washington on April 14, 1792. The Act set the number of members of the United States House of Representatives at 105, effective with the 3rd Congress on March 4, 1793, and established that a number of representatives would be allotted to each state based on the population enumeration provided by the 1790 Census. The final apportionment, which was not part of the Act itself, was on the basis of "the ratio of one for every thirty-three thousand persons in the respective States", and used the Jefferson method which required fractional remainders to be ignored when calculating each state's total number of representatives. This apportionment method continued to be used until the 1830 census. After discarding the remainders, the average population of congressional districts was 34,436 persons.

An earlier apportionment bill had been approved by the House in February 1792 and the Senate in March 1792, but was vetoed by the President on April 5, 1792. It was the first presidential veto of legislation in American history (and the history of modern democracies).