outsourcing agreementoutsourcing agreement: a legal agreement, common in business... More: a legal agreement, common in business to business contracts, pursuant to which a particular business function, rather than being performed in house, is outsourced to an external party for reasons that may include cost effectiveness or the principal business not having the expertise, infrastructure or resources to carry out that particular function in house; common in the technology law, where IT outsourcing contracts are used to outsource technology functions such as data processing, data storage and IT support.