The copyright symbol, or copyright sign, designated by © (a circled "C"), is the symbol used in copyright notices for works other than sound recordings (which are indicated with the ℗ symbol). The use of the symbol is described in United States copyright law, and, internationally, by the Universal Copyright Convention. The C stands for copyright.

The copyright symbol was introduced in the U.S. Copyright Act of 1909, section 18.

The copyright notice required by the U.S. Copyright Acts used to be a prescribed, lengthy formula: "Entered according to act of Congress, in the year         , by A. B., in the office of the Librarian of Congress, at Washington." In general, this notice had to appear on the copyrighted work itself, but in the case of a "work of the fine arts", such as a painting, it could instead be inscribed "on the face of the substance on which [the work of art] shall be mounted". The Copyright Act was amended in 1874 to allow a much shortened notice: "Copyright, 18        , by A. B."