001, O01, or OO1 may refer to:
Arts and entertainment 001, fictional British agent; see 00 Agent 001, also known as the Princess of Klaxosaurs, is a character and the central antagonist from DARLING in the FRANXX 001, a character in the 2016 Canadian Netflix science fiction series Travelers "001", an episode of the series' second season Player number of Oh Il-nam and Oh Young-il, characters in the South Korean drama Squid Game "001" (Squid Game episode), 2024 episode of Squid Game Subject designation number of Henry Creel, also known as Vecna or Mr. Whatsit, the main antagonist of the American science fiction horror series Stranger Things
Transportation AM-RB 001, the code-name for the Aston Martin Valkyrie sports car Zeekr 001, an electric shooting brake produced by Geely O01 Heussler Hamburg Heliport; see list of airports in New York
Science 1992 OO1, the asteroid 10111 Fresnel 1997 OO1, the asteroid 9987 Peano O01, an allele; see ABO
Other uses 1 (number), a numeral 001, former emergency telephone number for the Norwegian fire brigade (until 1986) Code for the world in the UN M49 standard for area codes Tyrrell 001, a Formula One racing car