United States Declaration of Independence (when used as "DoI"), the proclamation of independence from Great Britain

Takako Doi, a Japanese female politician.

United States Department of the Interior, a Cabinet department of the United States government that manages and conserves most federally-owned land

Digital object identifier, a persistent identifier given to digital objects on the Internet, e.g. documents, data, images

2,5-Dimethoxy-4-iodoamphetamine, a hallucinogenic drug

Doi, in Assamese language, means Curd

Yoichi Doi, a Japanese football player

Isami Doi (1903 - 1965), an American artist

Doi (or "Camera no Doi"), a Japanese distributor and retailer

Takero Doi, a Japanese economist.

Naruki Doi, a Japanese Professional Wrestler for Dragon Gate

Digital Opportunity Index, a standard developed by the International Telecommunication Union, an agency of the United Nations