An asylum seeker or asylum-seeker is a person who leaves their country of residence, enters another country, and makes in that other country a formal application for the right of asylum according to the Universal Declaration of Human Rights Article 14. A person keeps the status of asylum seeker until the right of asylum application has concluded.

The relevant immigration authorities of the country of asylum determine whether the asylum seeker will be granted the right of asylum protection or whether asylum will be refused and the asylum seeker becomes an illegal immigrant who may be asked to leave the country and may even be deported in line with non-refoulement. Signatories to the Universal Declaration of Human Rights create their own policies for assessing the protection status of asylum seekers, and the proportion of asylum applicants who are accepted or rejected varies each year from country to country.

The asylum seeker may be simultaneously recognized as a refugee and given refugee status if their circumstances fall into the definition of refugee according to the Convention relating to the Status of Refugees or regionally applicable refugee laws—such as the European Convention on Human Rights, if within the European Union.

The terms asylum seeker, refugee and illegal immigrant are often confused. In North American English, the term asylee is used both for an asylum seeker, as defined above, and a person whose right of asylum has been granted.

The right of asylum according to the Article 14 of Universal Declaration of Human Rights:

1. Everyone has the right to seek and to enjoy in other countries asylum from persecution.

2. This right may not be invoked in the case of prosecutions genuinely arising from non-political crimes or from acts contrary to the purposes and principles of the United Nations.

— Universal Declaration of Human Rights, Article 14