Portuguese Language Orthographic Agreement of 1990

The Portuguese Language Orthographic Agreement of 1990 (, ) is an international treaty whose purpose is to create a unified orthography for the Portuguese language, to be used by all the countries that have Portuguese as their official language. It was signed in Lisbon, on 16 December 1990, at the end of a negotiation, begun in 1980, between the Sciences Academy of Lisbon and the Brazilian Academy of Letters. The signatories included official representatives from all of the Portuguese-language countries except East Timor, which was under Indonesian occupation at the time, but later adhered to the Agreement, in 2004.