Alister is an anglicized spelling of the Scottish Gaelic Alasdair, the Scots form of Alexander, and so means "defender of men" or "protector of mankind". It has long been a Scottish favorite in various spellings, with Alistair and Alastair the most common. In the United States Alister is uncommon but steady: number 9137 in 2000, a best rank of number 1330 in 2022 and number 1689 in 2025.