Mr. Lambaste was once Amelia and Cleo's 6th grade English teacher. While Cleo was in 6th grade she put salt in his coffee as a prank. He suspected it was her and gave her detention for a month. Two years later Cleo's sister Amelia became his student. He guessed she was just like her older sister so he decided to treat her poorly. The following year he teaches Study Hall. It is unknown what subject he currently teaches or if he still teaches at Oopa Intermediate.
- Amelia's 6th-Grade Notebook (First appearance)
- Amelia's Most Unforgettable Embarrassing Moments (Mentioned only)
- Amelia's Guide to Gossip (Mentioned only)
- Amelia's 7th-Grade Notebook (Mentioned only)
- Amelia's Book of Notes & Note Passing (Mentioned only)
- Amelia's Guide to Babysitting (Mentioned only)