Rules for a Knight is a novel written by Ethan Hawke and illustrated by Ryan Hawke. The story takes place in the 15th century and is written in the form of a letter from the novel's protagonist, Sir Thomas Lemuel Hawke, to his four children. The novel recounts episodes of Sir Hawke's life as a knight and offers advice to the reader on a variety of topics such as love and chivalry.

Hawke has cited his own children and the rules of his home as inspiration for Rules for a Knight. He stated in an interview with The New Yorker, "What has been valuable about [the book] for me was that it gave me an excuse and permission to bring up subject matters that are very difficult to talk about with kids."

The book received some criticism for its "anachronistic nature", but was positively reviewed over all.

Rules for a Knight was published in a hardcover format on November 10, 2015, by Knopf publishing. It received mixed to positive reviews and appeared on The New York Times bestseller list at #12 during the week of December 6, 2015.

The book is divided into a preface, 20 subsections, and an end poem. Each of the 20 middle sections focuses on a different value or virtue explained in a short tale.

Preface – Thomas addresses a letter to his four children on the eve before a battle, fearing he will not survive it. The preface explains how he came as a young man to be the squire of his grandfather, who once served under King Henry V.

1. Solitude – recounts the telling of the fable of two wolves by Thomas's grandfather.

2. Humility – Thomas remembers a conversation with his grandfather and several other knights on the nature of humbleness, arrogance, and joy.