Juan de Borja y Castro was a Spanish noble of the House of Borja and the House of Castro. Borja was a soldier, diplomat and a worker for the Spanish state. He is best known for being the first Count of Mayalde and count consort of Ficalho.
- Occupation
- diplomat, writer
- Position held
- ambassador of Spain to the Kingdom of Portugal, Spanish envoy to the Holy Roman Empire
- Citizenship
- Crown of Aragon
- Born
- 1533
- Died
- September 3, 1606
