MacAlasdair is a masculine surname in Scottish Gaelic. The name translates into English as "son of Alasdair". The feminine form of the name is NicAlasdair, which translates into English as "daughter of Alasdair". These surnames originated as a patronyms, however they no longer refer to the actual name of the bearer's father. There are numerous Anglicised forms of MacAlasdair.