Hermione Granger earns ten O.W.L.s in the Harry Potter books.
O.W.L.s, or Ordinary Wizarding Levels, are important Hogwarts examinations taken at the end of a student’s fifth year. Hermione receives ten grades of “Outstanding,” showing her exceptional academic performance across the subjects she studies.
Harry and Ron do not take the same full set of subjects. Harry earns seven O.W.L.s, while Ron earns seven as well, though their grades differ. Hermione’s larger total reflects the unusually heavy workload created by her use of a Time-Turner during her third year.
The number is sometimes misremembered as eleven because Hermione initially studies many subjects. However, Divination and Muggle Studies are among the courses she later abandons, and the final examination result stated in the books is ten O.W.L.s.