Mr. Rhule is the Principal of Walkerville Elementary. He once ran a bet with Ms. 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.
- His serious demanour, appearance, and voice sounds a lot like Professor Oglevee from The Parkers