On his first day of high school at the formerly all-girl's Ousai Private Academy, Takatoshi Tsuda is called out for his untidy uniform by the student council president Shino Amakusa. In apology for delaying Takatoshi for his first class—and stating that the group needs a male point of view to accommodate the arrival of boys at the school—Shino offers him the position of vice president of the student council. Though unwilling, Takatoshi finds himself appointed as the newest member of the student council having yet to even step foot inside the school building. Takatoshi soon realizes that the other student council members who are more than a little strange: President Shino, who is studious and serious in appearance, but actually a huge pervert, fascinated with the erotic and constantly making lewd jokes; the secretary Aria Shichijou, who may seem like a typical sheltered rich girl, but is just as risque as the president, if not more so; and finally, the treasurer Suzu Hagimura, who may act fairly normal, but has the body of an elementary school student and is extremely self-conscious of it. Surrounded by these colorful characters, the new vice president must now work through a nonstop assault of sexual humor and insanity. [Written by MAL Rewrite]

It is the start of Takatoshi Tsuda's second year as the put-upon vice president of the student council and his sister Kotomi is entering school as a first year. New friends and double entendres are made. (Source: ANN)

They say that the more things change, the more they stay the same, and those words could not be more true for the student council of Ousai Private Academy. Though an entire year has passed—bringing the senior members to their final year of high school—not much has changed. President Shino Amakusa is just as perverted as ever, Secretary Aria Shichijou still refuses to put on a pair of panties, Treasurer Suzu Hagimura has yet to grow an inch, and Vice President Takatoshi Tsuda is still stuck as the straight man to their crazy antics. Of course, limiting the fun to a four-way might get a little stale; although the group still messes around with the Judo Club and the Newspaper Club, more girls have come to get in on the excitement. Takatoshi's sister Kotomi, a new student at Ousai, is as perverse as the president, while Uomi, the aloof student council president of the nearby Eiryou High School, fits right in with the insanity at Ousai. With loads of absurdity and sexual humor that keeps on coming, Takatoshi needs to harden up if he is going to keep up with all the madness around him. [Written by MAL Rewrite]

OVAs of Seitokai Yakuindomo* which were either bundled with the limited editions of the manga volumes or as standalone OVAs.