text: does string theory still have 10 dimensions or is it 11? a friend of mine told me that string theory has 11 dimensions but i have read that it has 10 dimnsions ,8 + 2 relativistic   who is right sring theory has 10,11 or even 26 dimensions depending on which of the five versions of string theory one ascribes to. however, all five versions were unified into m-theory in 1996. but most string theorists believe that it has 11 dimensions.  that includes 10 spatial and one temporal dimension.