In US military usage, a company officer is an US Army or US Marine commissioned officer below the rank of Major (abbreviated as MAJ): a Second Lieutenant (2LT), a (first) Lieutenant (1LT), or a Captain (CPT). Historically, these ranks made up the command element of a company. The term is used in distinction to those of field officer and general officer.

The corresponding United States Air Force term is "Company Grade Officer", usually abreviated as a CGO.