X class
- Class 10 (disambiguation)
- Mercedes-Benz X-Class
- Model yachting
- NCC Class X
- NER Class X
- NZR X class
- Nilgiri Mountain Railway X class
- Solar flare
- South Australian Railways X class
- TGR X class
- Tenth grade
- Victorian Railways X class
- Victorian Railways X class (diesel)
- WAGR X class
- X-class Melbourne tram
- X-class lifeboat
- X-class submarine
- X1-class Melbourne tram
- X2-class Melbourne tram