Naze Toudouin Seiya 16-sai wa Kanojo ga Dekinai no ka?

Seiya Toudouin's inability to answer one question has frustrated him to no end: "Why can't I get a girlfriend?" He gets the best grades, is fairly athletic, and, despite his modest opinion, is also rather good-looking. Even so, in all his 16 years of living, he has never once had a girlfriend. Every time he gets close to having one, he is left with bitter memories. Fed up with failures of the past, he sets a goal for himself—to finally get a girlfriend during high school!

Yet what comes easily for others soon becomes a strenuous task for Seiya, whose inexperience and social awkwardness only make his struggle greater. Nevertheless, he resolves to soldier on no matter how low the odds, based on his sheer conviction that a girlfriend is what he truly needs. But as he moves forward, the journey itself might give him a greater reflection of himself than any mirror could.

Toudouin Seiya was re-serialized in Japanese and English (as Why Can't I Get a Girlfriend?) through DeNA's Manga Box app from May 23, 2014 to August 28, 2015. During the Manga Box serialization, the original 39 chapters were split into 67.

The series inspired a 9-episode NBN TV drama series that aired from October 21 to December 16, 2014.