The Corwin Amendment is a proposed amendment to the United States Constitution that has never been adopted, but owing to the absence of a ratification deadline, could still be adopted by the state legislatures. It would shield slavery within the states from the federal constitutional amendment process and from abolition or interference by Congress. Although the Corwin Amendment does not explicitly use the word slavery, it was designed specifically to protect slavery from federal power. The outgoing 36th United States Congress proposed the Corwin Amendment on March 2, 1861, shortly before the outbreak of the American Civil War, with the intent of preventing that war and preserving the Union. It passed Congress but was not ratified by the requisite number of state legislatures.

Article Five of the United States Constitution describes the procedure for altering the Constitution. Under Article Five, the process to alter the Constitution consists of proposing an amendment or amendments, and subsequent ratification.