1U

1U may refer to:


 * ITA Software (IATA code)
 * 1U, a rack unit measurement
 * 1U server; see Pizza box form factor
 * RS-1U, a type of K-5 (missile)
 * J-1U, a model of Auster Workmaster
 * SSH 1U (WA); see Washington State Route 503
 * An abbreviation for 1 Utama
 * An abbreviation for "One Union" or "One Big Union", a concept and slogan used by industrial unionists, including the IWW. #1U is used also as a hashtag on social media by labor activists and organizations.
 * basic CubeSat size unit