The Solemn Fraggle Oath is used for situations with serious significance to the Fraggles. The words of the oath are "Weeba weeba, waffa waffa, garpox gumbage, whoopee!", while they hop in a circle.
When someone calls for the oath, others are required to swear, and only the Fraggle who called for the oath in the first place can release other Fraggles from it.
Episodes in which the oath is used include:
- "The Preachification of Convincing John": Mokey gets her friends, and later all of the other Fraggles, to swear the oath and promise to never eat Doozer constructions again after she figures eating them hurts the Doozer's feelings.
- "The Day the Music Died": The Fraggles all take the oath when they agree to help Gobo while he is writing The Glory Song.
- "Boober's Dream": Sidebottom makes Wembley swear that he will come back and visit with his other friends; later, Boober makes his friends swear that they won't promise such a thing to Sidebottom again. The oath is said yet again as Sidebottom promises Boober that he will not be too much fun in front of Boober's friends in the future.