Diego Martínez Belío is State Secretary for Foreign and Global Affairs of the Spanish Minister of Foreign Affairs, European Union and Cooperation.

Previously, he was Director of the Cabinet of the Spanish Minister of Foreign Affairs, European Union and Cooperation. A career diplomat, he has held various positions during his professional career, such as Director of the Cabinet of the Secretary of State for the European Union, Technical Advisor in the Cabinet of the Presidency of the Government, Deputy Consul of Spain in Casablanca, Second-in-Command at the Spanish Embassy in Malabo and Head of the Near East Service, among others.

He holds a Law degree from the Complutense University (Madrid) and the Sorbonne University (Paris) and a Diploma in Advanced Studies (DEA) in International Economic Law from the Sorbonne University. He joined the Diplomatic Service in 2007.