Jason Marsden (October 14, 2001) is Caillou Anderson's best friend in Caillou Gets Grounded and it's Sequel Caillou Gets Ungrounded. He's a bit of a smart aleck, but is much more intelligent than Caillou. He has trouble attracting women due to his small stature. He is voiced by Jason Marsden in Caillou Gets Grounded and Caillou Gets Ungrounded and by Hal Sparks in Caillou Gets Ungrounded.

Jason Marsden

  • In Caillou Gets Grounded: Caillou Iceskates he made a tape for Caillou that taught him how to ice skate in his sleep. Because the tape was originally about dieting, Caillou became obsessed with that also.


  • He was the only character on the series to have the same exact name of the actor portraying him.
  • Jason's birthday (October 14, 2001) is the same day that Actress Rowan Blanchard was born.
  • Jason is also voiced by Hal Sparks as Jason Marsden's Understudy marketing the third character that Sparks replaced Marsden the first two were Tak and the Power of JuJu television series based on the video games as Tak and the other Fuller House as Nelson Burkhard from Full House.
  • Jason wears a red shirt when he is voiced by Jason Marsden and wears a blue shirt when he is voiced by Hal Sparks.