Subunit

Subunit may refer to:
 * Subunit HIV vaccine, a class of HIV vaccine
 * Protein subunit, a protein molecule that assembles with other protein molecules
 * Monomer, a molecule that may bind chemically to other molecules to form a polymer
 * Sub-subunit, a military subunit is a component or subordinate element of a unit (military)
 * Subunit (format), test reporting and controlling protocol