If you're looking for manga similar to Tantei Gakuen Q, you might like these titles. All recommendations are made by Anime-Planet users like you!
Kiyotaka Narumi, a world-class detective, has been missing for two years. His last words prior to his mysterious disappearance were "I'm going to uncover the mystery of the Blade Children." These words have haunted Kiyotaka's younger brother Ayumu ever since, but neither he nor anyone else has gotten any closer to figuring out their meaning. But after Ayumu becomes the prime suspect in a murder, he begins to discover people with links to the 'Blade Children' all around him! Following in his brother's footsteps, Ayumu now must begin his own investigation into the mysterious Blade Children...
I never thought I would like the mystery genre until I watched and read Detective Academy Q, but I was wrong. Detective Academy Q has a great story line and great characters. Its two main characters, Kyu and Ryu are both awesome and geniuses in their own right. And it has amazing, amazing myteries that are complicated yet not quite unsolvable for us at home. In fact, you could say it has it all. When I read Spiral afterwards, however, I realized Academy Q had met its match. Everything and I mean everything that I mentioned above can be seen in Spiral, although Spiral has a bit more action in it. But one thing for certain is, if you loved Detective Academy Q, you will definitely love Spiral. And likewise, if you liked Spiral, I would highly recommend you read Detective Academy Q.