Kidhauer is the fan-given nickname of a student at Tom Landry Middle School who resembles Jeff Boomhauer; fans speculate that Boomhauer is his biological father. Kidhauer has never had a major role in the series; he appears sporadically throughout the series and speaks an occasional line. When he speaks he doesn't use Jeff Boomhauer's unique fast-talking style. He is almost always seen wearing a beige shirt and denim shorts. In earlier episodes he appeared to be a good friend of Bobby Hill's, but he eventually became a mere background character. His name was never revealed. When he spoke his voice was provided by Brittany Murphy or Lauren Tom.
- He is almost always seen with a T-shirt with the letters "K," and "H," on the chest, which may be his initails.