Lane v. Wilson, 307 U.S. 268 (1939), was a United States Supreme Court case that found a 12-day one-time voter registration window to be discriminatory for black citizens who were excluded from voting prior and repugnant to the Fifteenth Amendment.

[1] It eliminated the power of county registrars illegally excluding black citizens.

In 1915, the Supreme Court of the United States held in Guinn v. United States that a grandfather clause to Oklahoma's literacy test for voting was unconstitutional, violating the Fifteenth Amendment.

In response, the Oklahoma legislature passed a law giving citizens of the state a 12-day period, from April 30 to May 11, 1916, in which they were allowed to register to vote.

Justice Frankfurter delivered the ruling of the court, which held that Oklahoma's registration window and grandfather clause violated the Fifteenth Amendment to the United States Constitution.