What does the middle initial K stand for in J.K. Rowling’s name?

The K in J.K. Rowling stands for Kathleen, a name chosen in honor of her paternal grandmother. Rowling’s birth name was Joanne Rowling, so the initial was added before publication rather than inherited as part of her original name.

Her publisher requested two initials for the author name because research suggested that some boys might be less likely to choose a book written by a woman. Rowling had no middle name at birth, and she selected K from Kathleen, her grandmother’s name. The result became one of the most recognizable author names in modern publishing.

Readers sometimes assume that Rowling’s legal name is Joanne Kathleen Rowling. The initial is widely used in her professional identity, but the important publishing story is that Kathleen was adopted as a tribute and to create the requested two-initial pen name.