A passport is a document, issued by a national government, which certifies, for the purpose of international travel, the identity and nationality of its holder. The elements of identity are name, date of birth, sex, and place of birth.

A passport does not of itself entitle the passport holder entry into another country, nor to consular protection while abroad or any other privileges. It does, however, normally entitle the passport holder to return to the country that issued the passport. Rights to consular protection arise from international agreements, and the right to return arises from the laws of the issuing country. A passport does not represent the right or the place of residence of the passport holder in the country that issued the passport.

One of the earliest known references to what served the major role of a passport is found in the Hebrew Bible. In Nehemiah 2:7-9, attributed to the time of the Persian Empire in about 450 BC, it is said that Nehemiah, an official serving King Artaxerxes I of Persia, asked leave to travel to Judea, and the king granted leave and gave him a letter "to the governors beyond the river" requesting safe passage for him as he travelled through their lands.

In the medieval Islamic Caliphate, a form of passport was used in the form of a bara'a, a receipt for taxes paid. Only citizens who paid their zakah (for Muslims) or jizya (for Dhimmis) taxes were permitted to travel to different regions of the Caliphate, thus the bara'a receipt was a "traveller's basic passport."