Two spellings of the name exist in English: "Macao", derived from the original Portuguese spelling; and "Macau", derived from the current orthography. Since the transfer of sovereignty over Macau in 1999, the government of Macau considers both "Macau" and "Macao" to be acceptable spellings of the name in English language publications, but the former was more widely used across English-speaking world, especially in the United States and Australia.
The name Macau is spelled differently depending on the origin of its use: Portuguese and current English orthography.