4-H is a youth organization administered by the USDA.

4H may also refer to:

• Curtiss JN-4H, an American biplane
• 4H, a Washington, D.C. Metrobus route
• 4H-pyran
• 4H-SiC, one of the polymorphs of silicon carbide
• ⁴H (quadrium), An Isotope of Hydrogen.

See also

• H4 (disambiguation)

it:4H