Sir Roderick Glossop is a recurring fictional character in the comic novels and short stories of P. G. Wodehouse. Sometimes referred to as a "nerve specialist" or a "loony doctor", he is a prominent practitioner of psychiatry in Wodehouse's works, appearing in several Jeeves stories and in one Blandings Castle story.

Though he is initially antagonistic towards Bertie Wooster, they become friends in later stories.

The character of Sir Roderick Glossop was inspired by Dr. Henry Crawford MacBryan, who operated a psychiatric nursing home in the hamlet of Ditteridge, in the parish of Box, Wiltshire, near Cheney House where the young Wodehouse spent some of his childhood with his aunts.

Sir Roderick Glossop is the father of Honoria Glossop and Oswald Glossop. He is first married to Lady Glossop, a friend of Bertie's Aunt Agatha, and later to Lady Chuffnell, aunt of "Chuffy", Lord Chuffnell. He went to school with Lord Emsworth, who states that Glossop was an unpleasant boy who had a nasty and superior manner. Glossop has a pleasant baritone voice, and as a penniless medical student, sang at smoking concerts. His residences are 6b Harley Street and Ditteredge Hall, Hampshire.

He is formally called a nerve specialist or a brain specialist, though Bertie thinks of him as a "high-priced loony-doctor". Even after they become friends, Bertie still refers to Glossop as "the eminent loony doctor". He is a well-known psychiatrist, and, according to Bertie, "practically every posh family in the country has called him in at one time or another". He is described as serious-minded by Bertie Wooster's Aunt Agatha, who tells Bertie that Sir Roderick is President of the West London branch of the anti-gambling league, drinks no wine, disapproves of smoking, and, due to an impaired digestion, can only eat simple food. She also says that he does not approve of coffee, as he considers it "the root of half the nerve-trouble in the world."

When Bertie sees Glossop in "Sir Roderick Comes to Lunch", he describes Glossop as an "extraordinarily formidable old bird," stating:

He had a pair of shaggy eyebrows which gave his eyes a piercing look which was not at all the sort of thing a fellow wanted to encounter on an empty stomach. He was fairly tall and fairly broad, and he had the most enormous head, with practically no hair on it, which made it seem bigger and much more like the dome of St Paul's. I suppose he must have taken about a nine or something in hats. Shows what a rotten thing it is to let your brain develop too much.

In that story, Glossop has lunch with Bertie to judge whether or not Bertie is mentally sound and fit to marry Honoria. Incidents arise that lead him to render a negative judgment, especially when Glossop, who strongly dislikes cats, is surprised by three cats in Bertie's flat. This incident is often recounted in later stories, with the number of cats being exaggerated as twenty-three. In "Bingo and the Little Woman", Glossop corroborates a claim that Bertie is mentally unsound. These stories appear in The Inimitable Jeeves.