Any organization, public or private, that pays or insures health care expenses for beneficiaries at the time when they are patients.

Refers to situations where the first party (the patient) does not pay directly for the activities of the second party (the health care provider), but where this is done through a private insurer, sickness fund, or government agency (the third party payer).

World Health Organization. European Observatory on Health Systems and Policies. Glossary. 2009.