"L.T.'s Theory of Pets" is a short story written by Stephen King. It was originally published in his 1997 limited-edition collection Six Stories, and later included in his 2002 collection Everything's Eventual.
The story is told from a first-person perspective about a working class husband who recalls a story told by L. T., a chatty co-worker who recalls the brewing trouble behind his marriage, attributed to pets purchased by L. T. and his wife. His wife purchased a dog for L. T. which in turn, disliked him instantly and sided with the wife, while L. T. purchased a cat for his wife, who immediately took to L. T. Despite the fact that the dog and the cat get along fine, L. T. and his wife continuously argue, adding some irony. His wife then leaves L. T. and said she has gone to her mother's, which actually never happened. L. T. starts to bawl in the narrator's car.