Haunted Junction

When I first started watching Gakkou no Kaiden, the general theme really reminded me of Haunted Junction. I only watched the sub of Gakkou no Kaiden so I can't be sure but having seen clips of the dub, the humour between the Gakkou no Kaiden dub and Haunted Junction seem to be similar. As far as the sub goes Haunted Junction is a lot more comedy based but I personally think they're similar in a couple ways, though I enjoyed Gakkou no Kaiden much more. 

In both series there are 3 main characters and there job is to track down ghosts in there school. They have a very similar feel to each show. The difference in haunted junction is that there are 7 mysterious ghost tails in the school and they hunt down each ghost. It's a great comedy and beautiful art.  

Both of these series are supernatural comedies that feature a variety of amusing characters and seiyuu Mariko Kouda is in both anime portraying a ghost girl/sprit, Okinu in Ghost Sweeper Mikami and Hanako in Haunted Junction.  

If you're looking for something with similiar drawing style to later Ranma ½ series, Haunted Junction has that and vice versa, also character expressions are super similiar + both are comedies. 

Human in a school full of monsters and ghosts. Not the best but the funny situations of a scared christian boy in a haunted japanese school full of wierdo classmates who look up to him is worth a good laugh.