He will take over from the current Archbishop Dr George Carey in October.
He is described as being "a liberal".
This means he's open to new ideas and is keen on interpreting The Bible in ways that make sure it remains relevant and important.
Dr Williams is known as one of the cleverest people involved in religion, and his ability to make people understand The Bible has been praised highly.
However some other members of the church are worried about his new ways of thinking and want him to explain some of the changes he might make.