Mr. Small's office is a relatively small, sparsely furnished room. There are two small chairs directly in front of Mr. Small's desk, and a large row of wooden filing cabinets near the door. In "The Phone," it is revealed that Mr. Small keeps a box of the things he confiscates on his desk, though it is only shown in that episode.
- "The Sock": Its debut. Gumball and Darwin constantly visit it throughout the episode.
- "The Fight": Gumball and Anais visit Mr. Small's office to get some advice on dealing with bullies.
- "The Banana": Gumball, Darwin, and Banana Joe are sent here.
- "The Phone": Gumball retrieves Darwin's cellphone from the box here.
- "The Words": Darwin is sent to the office for reckless behaviour.
- "The Sidekick": It appears during a few of Tobias' many excuses for returning the game late.
- "The Photo": Mr. Small can be seen meditating in his office.
- "The Lesson": Principal Brown sends the boys to the dreaded "correctional room" as punishment for trashing his office. It turns out to be Mr. Small's office.
- "The Sweaters": Gumball and Darwin go to Mr. Small about their problem with Carlton and Troy.
- "The Finale": Both Gumball and Darwin tuck Mr. Small into an envelope, with the latter creating a small mess off his desk before leaving.
- "The Fraud": Mr. Small comes out of his office to stop Principal Brown.
- "The Void": Gumball and Darwin go into the office and find Mr. Small meditating.
- "The Allergy": Mr. Small attempts to treat Darwin with unconventional medicine here.
- "The Return": It is briefly seen when Mr. Small is swept away by the balls.
- "The Others": It appears during the intro for The So Called World of Clare.
- "The Comic": Mr. Small opens the door when singing LaserHeart's theme.
- "The Advice": Mr. Small gives the "Beginners' Advice" to Gumball and Darwin.
- "The Scam": Mr. Small is mediating in his office.
- Various posters cover the walls, including one promoting good nutrition that reads: "Remember your 5 a Day," one that promotes kindness with an illustration of two anthropomorphic houses hugging and reads: "Love Thy Neighbor," one that discourages bullying with an illustration of someone who oddly resembles Mr. Robinson with the text reading: "Bully Free Zone," a poster featuring the World Peace day of 1972, and a Star Chart directly behind Mr. Small's desk.