|It's a Happy, Happy, Happy Happy World|
|Season 4, Episode 18|
|Air Date||April 16th, 2016|
|Written by||Eric Rogers|
|Supervising director||Joel Dickie|
|Directed by||Steven Garcia|
|A Doggie Biskit||Race Team: Buttercream|
It's a Happy, Happy, Happy, Happy World is the eighteenth episode of the fourth season of Littlest Pet Shop and the ninety-sixth episode overall.
- Ashleigh Ball - Blythe Baxter
- Sam Vincent - Russell Ferguson, Josh Sharp, and Waiter
- Tabitha St. Germain - Pepper Clark
- Kyle Rideout - Vinnie Terrio
- Kira Tozer - Minka Mark
- Nicole Oliver - Zoe Trent
- Peter New - Sunil Nevla and Hipster Cat
- Jocelyn Loewen - Penny Ling
- Kathleen Barr - Mrs. Twombly
- Brooke Goldner - Peachie Fluffton
- The hamster tubes from Hamster Hoods and Pitch Purrfect return.
- The poodle from Ivan the Terrific makes a cameo.
- Betty's journal from the first two episodes of Season 4 appear.
- Blythe mentions how Josh was in the costume in Game of Groans.
- The title and plot is somewhat similar to the famous film, It's a Mad, Mad, Mad, Mad World.
- Pepper has acrophobia.
- Minka tries to say "Come with me if you want to live" which is a quote from the film Terminator. But she can't remember which correct word is used.
- The pigeon that Russell and Pepper ride on to find Sunil is drawn and behaves in a more realistic way compared to the other animals in the series.
- Brooke Goldner reappears after the season 2 finale, which aired 2 years ago.