David Melgueiro (Porto, ? – Porto, 1673?) is alleged to have been a Portuguese navigator and explorer. He allegedly sailed across the Northeast Passage in 1660 by travelling from Japan to Portugal through the Arctic Ocean at a time when Portuguese vessels were banned from Japan. The story is considered to be a falsehood, with obvious factual errors in the account of the voyage and no historical evidence to support it or even confirm Melgueiro's existence.