1977

The year 1977 was the twentieth year Hanna-Barbera was in the business.

• September 10:
  • "The Curse of the Viking Lake," the seventeenth episode of The Scooby-Doo Show, premiered.
  • "The Swiss Alps and Tokyo, Japan," the first episode of Laff-a-Lympics, premiered.
  • "The Missing Mansion Mystery," the first episode of CB Bears, premiered.
  • "Buzzard, You're a Turkey," the first episode of Blast-Off Buzzard, premiered.
  • "The Blue Kangaroo," the first episode of Heyyy, It's the King!, premiered.
  • "Big Duke and Li'l Lil," the first episode of Posse Impossible, premiered.
  • "Guess What's Coming to Dinner," the first episode of Shake, Rattle and Roll, premiered.
  • "The Sneaky Sheik," the first episode of Undercover Elephant, premiered.
• September 17:
  • "Vampire Bats and Scaredy Cats," the eighteenth episode of The Scooby-Doo Show, premiered.
  • "Acapulco and England," the second episode of Laff-a-Lympics, premiered.
  • "The Doomsday Mine," the second episode of CB Bears, premiered.
  • "Hard Headed Hard Hat," the second episode of Blast-Off Buzzard, premiered.
  • "The First King on Mars," the second episode of Heyyy, It's the King!, premiered.
  • "Trouble at Ghostarado," the second episode of Posse Impossible, premiered.
  • "The Ghostly Ghoul is a Ghastly Guest," the second episode of Shake, Rattle and Roll, premiered.
  • "Baron Von Rippemoff," the second episode of Undercover Elephant, premiered.
• September 24:
  • "Hang In There, Scooby-Doo," the nineteenth episode of The Scooby-Doo Show, premiered.
  • "Florida and China," the third episode of Laff-a-Lympics, premiered.
  • "Follow That Mountain," the third episode of CB Bears, premiered.
  • "Hearts and Flowers, Buzzards and Snakes," the third episode of Blast-Off Buzzard, premiered.
  • "The Riverbed 5000," the third episode of Heyyy, It's the King!, premiered.
  • "The Not So Great Train Robbery," the third episode of Posse Impossible, premiered.
  • "There's No Pest Like a Singing Guest," the third episode of Shake, Rattle and Roll, premiered.
  • "The Moanin' Lisa," the third episode of Undercover Elephant, premiered.
  • "Madame Ape Face," the nineteenth episode of Dynomutt, Dog Wonder, premiered.