The new law, passed in December, is supposed to take effect Wednesday. Court papers filed Monday with Chief Justice John Roberts argue that Washington residents should be able to vote on the matter. Local courts have rejected the opponents' arguments.
The gay marriage opponents include a Baptist minister, Walter E. Fauntroy, who was Washington's delegate in the House for almost 20 years.
The city has said Wednesday probably will be the first day same-sex couples can apply for a marriage license. Couples will still have to wait three full business days for their licenses before exchanging vows.