An apostille is a certificate defined by the 1961 Hague Apostille Convention that verifies the authenticity of a public document so it can be accepted in any other member country. When both the issuing country and the destination country are parties to the convention, a single apostille replaces the longer embassy-by-embassy attestation chain.
This matters for the GCC because several countries in the region have joined the Apostille Convention, which can simplify how foreign degrees, civil-status certificates, and similar documents are recognized. Where one of the two countries is not a member, the traditional attestation route through embassies and foreign ministries still applies.
Because membership and acceptance rules are evolving, applicants should check whether both countries involved are convention members and whether the destination authority accepts an apostille for their specific document.