This is a list of notable events, premieres, releases, series cancellations and endings, and other business ventures for Nickelodeon in the year 2008.
- February 7: Ni Hao, Kai-Lan
- March 29: Dance on Sunset
- April 26: The Mighty B!
- July 11
- Queen Bees
- The N's Student Body
- September 15: My Family's Got GUTS
- October 4: Making Fiends on Nicktoons Network
- November 8: True Jackson, VP
- November 16: Rugrats Pre-School Daze
- November 28: The Penguins of Madagascar (sneak peek)
- December 6: Random! Cartoons on Nicktoons Network
- Acquired shows (premieres)
- January 21: Ricky Sprocket: Showbiz Boy on Nicktoons Network
- May 2: Speed Racer: The Next Generation on Nicktoons Network
- November 16: Toot & Puddle on Noggin
- Acquired shows (reruns)
- June 29: Family Matters
- January 21: The Naked Brothers Band, season 2
- January 27: Zoey 101, season 4
- February 1: The Backyardigans, season 3
- February 18: The Fairly OddParents, season 6 (first post-revival)
- March 3: SpongeBob SquarePants, season 6
- September 2: Wow! Wow! Wubbzy!, season 2
- September 6: Pinky Dinky Doo, season 2
- September 7: Dora the Explorer, season 5
- September 22: Yo Gabba Gabba!, season 2
- September 27: iCarly, season 2
- October 4: My Life as a Teenage Robot, season 3 (on Nicktoons Network)
- October 18: The Naked Brothers Band, season 3
- February 18: The Fairly OddParents: "Fairly Odd Baby"
- July 16: Avatar: The Last Airbender: "The Boiling Rock"
- July 19: Avatar: The Last Airbender: "Sozin's Comet"
- August 18: Go, Diego, Go!: "Diego's Moonlight Rescue"
- November 3: Dora the Explorer: "Dora Saves the Snow Princess"
- April 5: Just Jordan, two seasons
- May 2: Zoey 101, four seasons
- June 21: Dance on Sunset, one season
- July 19: Avatar: The Last Airbender, three seasons
- August 17: All Grown Up!, five seasons
- August 23: ChalkZone, four seasons
- August 24: The N's Student Body, one season
- August 29: Queen Bees, one season
- September 13: El Tigre: The Adventures of Manny Rivera, one season
- September 17: Wayside, two seasons (Nicktoons Network)
- September 20: Kappa Mikey, two seasons
- August 29: Wow Wow Wubbzy: Wubbzy's Big Movie!
- September 12: Gym Teacher: The Movie
- November 8: iCarly: "iGo to Japan"
- December 5: Merry Christmas, Drake & Josh
- January 1: Teamwork Saves the Day!
- July 29
- Flyboat Adventures
- Go, Wonder Pets!
- The Wonder Pets Save the Dinosaur!
- Let's Count Baby Animals!
- Good Night, Wonder Pets!
- The Wonder Pets Save the Hedgehog!
- August 26
- Save the Bengal Tiger!
- We Can Help!
- October 7: Wonder pets!: save the reindeer!
- October 21: Ming-Ming Saves the Day
- October 28: Let's Find Colors!
- December 16: The Wonder Pets Love You!
- December 23: Join the Circus
- January 23: SpongeBob's Atlantis SquarePantis SquareOff
- June 29: Nicktoons: Android Invasion
- Nicktoons Nitro
- Nicktoons Slimeball Multiplayer
- September 15: Drawn to Life: SpongeBob SquarePants Edition
- October 13
- Avatar: The Last Airbender – Into the Inferno
- Tak and the Guardians of Gross
- Tak: Mojo Mistake
- October 13: Back at the Barnyard: Slop Bucket Games
- October 17: The Naked Brothers Band
- October 20: SpongeBob SquarePants featuring Nicktoons: Globs of Doom
- October 27:
- Dora The Explorer: Dora Saves The Snow Princess
- The Wonder Pets! Save the Animals!
- October 29: Go, Diego, Go!: Great Dinosaur Rescue
- October 31: Avatar: The Last Airbender – Into the Inferno (European release)
- January 29: SpongeBob SquarePants: To Love a Patty
- February 5: Go, Diego, Go!: Diego's Magical Missions
- February 12: Wonder Pets!: Save the Dinosaur!
- February 26
- March 18: Go, Diego, Go!: Moonlight Rescue
- April 15: SpongeBob SquarePants: Pest of the West
- April 22: Wonder Pets!: Save the Beetles!
- April 29: Are You Afraid of the Dark?: Season 6
- May 13: The Backyardigans: High Flying Adventures!
- June 3
- Go, Diego, Go!: Great Gorilla!
- Wonder Pets!: Save the Nursery Rhyme!
- June 24: Tak and the Power of Juju: The Trouble with Magic
- July 1: Zoey 101: The Complete 3rd Season
- July 8: The Backyardigans: Mighty Match-Up!
- August 5: Back at the Barnyard: When No One's Looking?
- August 12: Ni Hao, Kai-Lan: Super Special Days!
- August 19: Are You Afraid of the Dark?: Season 7
- August 26: Go, Diego, Go!: Diego's Halloween!
- August 29: Zoey 101: The Complete 2nd Season
- September 9: Wonder Pets!: Save the Bengal Tiger!
- September 16: Avatar: The Last Airbender: The Complete Book 3 Collection
- September 23: iCarly: Season 1, Volume 1
- September 30: Dora the Explorer: Dora's Out-Of-This-World Adventures
- October 7
- The Backyardigans: Escape from Fairytale Village!
- Wonder Pets!: Save the Nutcracker!
- October 14: SpongeBob SquarePants: WhoBob WhatPants?
- October 21: Go, Diego, Go!: It's a Bugs' World
- November 3
- SpongeBob SquarePants: The Ultimate Box Set (international release)
- Dora the Explorer: Ultimate Box Set (international release)
- November 1: Zoey 101: The Complete 4th Season
- November 18
- The Fairly OddParents: Season 6, Volume 1
- SpongeBob SquarePants: Season 5, Volume 2
- August 21
- August 29
- The Best of Drake & Josh: Seasons 3 & 4
- Doug: Season 1
- Doug: Season 2
- Hey Arnold!: Season 2
- September 5
- The Adventures of Jimmy Neutron: The Best of Season 1
- The Adventures of Jimmy Neutron: The Best of Season 2
- The Adventures of Jimmy Neutron: The Best of Season 3
- September 16
- September 23
- Ned's Declassified School Survival Guide: The Best of Season 1
- Ned's Declassified School Survival Guide: The Best of Season 2
- December 19: Merry Christmas, Drake and Josh
- January 28: Kappa Mikey: Season Two
- February 6: Zoey 101: Season Four
- February 18: The Fairly OddParents: Season Six
- April 28: Mighty B!: Season One
- June 9: Yo Gabba Gabba!: Season One
- June 16: Hey Arnold!: Volume One
- June 18: The Best of Rugrats: Volume One
- July 28
- September 15
- September 27: iCarly: Volume Two
- November 9: True Jackson, VP: Season One
- Nickelodeon starts allowing Amazon.com to produce DVDs of their shows and movies through the CreateSpace manufacture-on-demand program.
- March 10: Zoe Glick (actress on Bubble Guppies)
- April 17: Matthew Mucci (actor on Blue's Clues and You!)
- April 18: Evangeline Lomelino (actress on The Loud House)
- April 21: Malachi Sanchez (YouTuber)
- April 25: Asher Bishop (voice actor on The Loud House)
- June 20: Taylor Kaplan (actress on Bubble Guppies)
- July 2: Leah Janvier (actress on Bubble Guppies)
- July 14: Morgan McGill (actress on A Loud House Christmas and the live-action Loud House series)
- July 15: Iain Armitage (voice actor on PAW Patrol: The Movie)
- July 20: Beckett Hipkiss (actor on PAW Patrol)
- August 1: Emma Berman (actress on Abby Hatcher)
- August 5: Shechinah Mpumlwana (voice actress on Corn and Peg and Blue's Clues & You!)
- August 29: Ava Augustin (voice actress on Blue's Clues & You!)
- September 8: Jet Miller (actress on Tyler Perry's Young Dylan)
- November 3: Audrey Grace Marshall (actress on The Fairly OddParents: Fairly Odder)
- November 5: Brock Duncan (actor on Tyler Perry's Young Dylan)
- November 23:
- December 5: Cande Calvin (actress on Nella the Princess Knight)
- December 29: Luke Lowe (actor on Kinderwood)
- Wyatt White (voice actor on PAW Patrol and Abby Hatcher)
- May 29: Harvey Korman (voice actor on Hey Arnold! and The Wild Thornberrys)
- June 15: Henri Labussière (actor on Rugrats in Paris: The Movie)
- June 29: Greg Burson (voice actor on The Angry Beavers and CatDog)
- December 5: Beverly Garland (actress on The Angry Beavers)
- December 25: Eartha Kitt (actress in Harriet the Spy, The Wild Thornberrys, Wonder Pets!, and My Life as a Teenage Robot)
Nickelodeon character debuts
- The Fairly OddParents: Poof
- Wow! Wow! Wubbzy!: Daizy
- Random! Cartoons: Finn the Human, Jake the Dog, Princess Bubblegum, Ice King, Lady Rainicorn, Gunter