Eligible countries:described in Annex B of the Work Programme General Annexes. A number of non-EU/non-Associated Countries that are not automatically eligible for funding have made specific provisions for making funding available for their participants in Horizon Europe projects. See the information in the Horizon Europe Programme Guide.
For other eligibility criteria, see https://commission.europa.eu/strategy-and-policy/eu-budget/how-it-works/annual-lifecycle/implementation/anti-fraud-measures/edes/edes-database_en.