Class 1
- Appliance classes
- Class 01 (disambiguation)
- Class 1 Touring Cars
- Class 1 World Powerboat Championship
- Class I (disambiguation)
- Class I railroad
- Classes of United States senators
- First class (disambiguation)
- HAZMAT Class 1 Explosives
- Laser safety
- NSB Di 1
- NSB El 1
- National Insurance
- SCORE Class 1
- Type 1 (disambiguation)
- Yosemite Decimal System