Mr. Ruhle is the principal of Walkerville Elementary. He once ran a bet with Professor Frizzle on whether or not she could beat the light pinball machine she and Liz had built (Makes a Rainbow). He is an expert on chickens, owning a Rhode Island Red rooster named Giblets, who Dorothy Ann had accidentally lost in Cracks a Yolk.
In the original series, he was voiced by the late Paul Winfield. In Rides Again, he is voiced by Martin Roach.
- There are pictures of Giblets on his wall in the original series, implying that he has a bond with an animal, just like the Frizzle sisters and Goldie/Liz.
- It's revealed in Carlos Gets the Sneezes that he is allergic to rats.