What is J.K. Rowling’s middle initial short for?

J.K. Rowling’s middle initial K stands for Kathleen.

She was born Joanne Rowling, without a middle name. When her first Harry Potter book was prepared for publication, Bloomsbury asked her to use initials rather than her full name because the publisher believed that boys might be less likely to choose a book written by a woman. Rowling selected K in honor of her paternal grandmother, Kathleen.

The resulting author name was J.K. Rowling, even though Kathleen was not part of her original birth name. Rowling has also been known publicly as Joanne Rowling and Jo Rowling. Her initials became inseparable from the Harry Potter brand and were retained across the seven main novels.

Readers sometimes assume that the K was a childhood middle name or that it stands for Rowling’s own name. Neither is correct. Kathleen was added as a publishing name, and the choice reflects a family connection rather than a change to the author’s legal birth identity.