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

• U1 (disambiguation)