Mr. Crabtree is an elderly man who appears in The Secret of the Unicorn.
One day, a flea market event was being held in Brussels, and Mr. Crabtree took part as a vendor selling various items, including a model of The Unicorn, a 16th century sailing ship once captained by Sir Francis Haddock. On the same day, Tintin visited the flea market and became interested in buying the model of The Unicorn Crabtree was selling as a gift for Captain Haddock. While two other men Ivan Ivanovitch Sakharine and Barnaby Dawes attempted to acquire the model themselves, Crabtree already reserved the model to Tintin after purchasing it. Although he only appeared in the the beginning of the story, he played an important role in the case of the goal to acquire all three of Sir Francis' models of The Unicorn unlocking the location of the treasure once owned by the infamous pirate Red Rackham.
- He was never referred to by name in the orignal Secret of the Unicorn book, but was later given one for the 2011 motion-capture film The Adventures of Tintin: The Secret of the Unicorn.