Catherine “Kitty” Bennet is the fourth of the Bennet sisters. She is pretty and delicate, coughing frequently enough that her parents complain and Mr. Bingley even comments that a walk of a certain length would be too much for her. This fragility is reinforced through her behavior and relationships, especially as it pertains to her youngest sister, Lydia. Although she is technically older than Lydia, Kitty very much behaves as her shadow, adopting a passivity that is normally attributed to younger siblings. The two sisters are practically joined at the hip, and when the militia comes to town, Kitty is just as consumed as Lydia by the prospect of securing one of the members of the regiment for a husband. Kitty is considered by her father to be very silly, having no measure of sense about the world or how to operate in good propriety.

Kitty ties her sense of identity to Lydia so thoroughly that she doesn’t know what to do or how to behave when she’s gone, becoming almost despondent when Lydia is invited by Colonel Forster's wife to accompany them to Brighton. While she defers to Lydia for most things, Kitty does possess a capability for understanding that Lydia does not. She is disconcerted when their father insults them, whereas Lydia does not care. And when Mrs. Bennet demands all the sisters leave so Elizabeth can speak to Mr. Collins alone, Kitty goes, while Lydia stays behind to eavesdrop. When Lydia moves away after marrying Mr. Wickham, Kitty spends more time with Jane and Elizabeth and benefits from her proximity to them—growing less irritable, less insipid, and less ignorant in Lydia’s absence.