The title comes from the last scene in the book. Braithwaite has endured a long journey with his students. He has helped in transforming them from rude and discarded youth to mature "productive members of society." Both he and the students have come very far. Their journey has ended up changing them both. He has moved from one who was uncertain his path to a "teacher," an architect of student learning. They have come equally as far, from being a group of "teacher baiting" students, to individuals who are mindful of what their future holds for them.
On the last day, the group of students present Braithwaite with a gift. The tag on the package reads, "To Sir, With Love" and all of the students have signed it. Braithwaite is taken aback at this moment. The selflessness of the kids giving him a gift is so very far from where they were when this journey began. Another reason why he is taken back is in how all of them acted as a group for his benefit. Finally, in holding the gift, and seeing "To Sir, with Love," written on the tag, Braithwaite knows that he has found his career, his vocation. With the headmaster watching, Braithwaite pours over those words written on the tag and the names of the students, his students, written underneath. These four words serve as the title of the book. They embody both what Braithwaite experienced as a teacher and capture the essence of his journey with his students.