Commercial office space is building space dedicated to administrative work for private companies. The majority of office buildings fit this category. If a multi-tenant office building has a mixed roster of commercial and institutional or governmental tenants, then it is considered commercial space.

Office space is generally regarded as commercial on the basis of its market-rate availability, but space which is leased by institutions, governments, militaries, etc. can be listed as institutional, government, or military office space if the sole lessee takes control of the space's identification.

The identification of the premises can follow a sole institutional or public tenant that controls the space. A mixed roster in a commercial multi-tenant building does not by itself change the whole building to institutional or government office use.