W21 (disambiguation)

The W21 was a hydrogen bomb design for the US military.

W21 may also refer to:

• British NVC community W21, a scrub community in the British National Vegetation Classification system
• Mercedes-Benz W21, a German sedan
• Samsung W21 5G, a smartphone
• Wanderer W21, a German sedan
• Wilderness 21, an American sailboat
• The AIATSIS designation for the Tharrkari language
• The Wenninger index number for a Great dodecahedron