• 
  Andy Berman

  Dib
• 
  Lucille Bliss

  Ms. Bitters
• 
  Melissa Fahn

  Gaz
• 
  Mo Collins

  Zita
• 
  Danny Cooksey

  Melvin
• 
  David Herman

  Assistant #1 / Assistant #2 (voice)
• 
  Richard Steven Horvitz

  ZIM
• 
  Kerri Kenney

  Invader Tenn

• 
  Kevin McDonald

  Almighty Tallest Purple
• 
  Kevin Michael Richardson

  Smikka Smikka Smoogoo
• 
  Rosearik Rikki Simons

  GIR
• 
  Mindy Sterling

  Countess von Verminstrasser
• 
  Fred Tatasciore

  Neighbor
• 
  Wally Wingert

  Almighty Tallest Red
• 
  Antoinette Spolar

  Gretchen