Novels

• The Day My Bum Went Psycho (2001) Published in the US as The Day My Butt Went Psycho
• Zombie Bums from Uranus (2003) Published in the US as Zombie Butts From Uranus
• The Final Pongflict (2005) Published in the US as " The Final Conflict"
• Fast Food and No Play Make Jack a Fat Boy (2006)
• What Bumosaur is That? (2007) Published in the US as "What Buttosaur is That?"
• What Body Part is That? (2011)

Short story collections

• The Bad Book (2004)
• The Cat on the Mat Is Flat (2006)
• The Big Fat Cow That Goes Kapow! (2008)
• The Very Bad Book (2010)
• The Super Bad Book (2011)

Schooling Around series

• Treasure Fever! (2008)
• Pencil of Doom! (2008)
• Mascot Madness! (2009)
• Robot Riot! (2009)

Just! Series

• Just Tricking! (1997) Published in the US as " Just Joking! Published in New Zealand as " Just Kidding!
• Just Annoying! (1998)
• Just Stupid! (1999)
• Just Crazy! (2000) Published in the US as " Just Wacky "
• Just Disgusting! (2002)
• Just Shocking! (2007)
• Just Writing! (2011)
• Just Three for Free- Contains Playing Dead (Just Tricking), In The Shower with Andy (Just Annoying) and Runaway Pram (Just Stupid).

At a live appearance at Marion Library in Marion, Australia, Griffiths stated that he will be releasing a new Just! book, entitled "Just Writing!". The release date is yet to be announced.

Just Macbeth!

In 2007, Griffiths wrote Just Macbeth!, a modern version of the play Macbeth, by William Shakespeare, starred by the Just! series characters. It was produced by Bell Shakespeare Company. A book adaption was released in July 2009.