Asked whether the American actress's previous marriage to film producer Trevor Engelson posed a barrier, Most Rev Justin Welby said "clearly, it's not a problem". Engelson and Markle married in 2011 and split in 2013.
Speaking during a press conference attended by Premier at Lambeth Palace, Archbishop Justin said: "The Church of England has rules about how you deal with that and we've dealt with that.
"The Church of England has a very clear statement on the nature of when people who have been divorced who have a previously partner still living can get married and we went through that."
Since 2002, a divorcee may be allowed to marry again in the Church of England during the lifetime of a former spouse in "exceptional circumstances".
Prince Harry and Ms Markle announced their engagement last November.
The Church, which teaches that marriage is "for life", allows clergy discretion in whether they decide to officiate at such a marriage or allow the use of their church for the occasion.
Archbishop Justin, who will officiate at the ceremony inside St George's Chapel, Windsor Castle at midday on 19th May, said he is "looking forward to it enormously".
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