Kei Kusanagi is a high school boy living with his aunt and uncle in Onegai☆Teacher. One otherwise ordinary day, he encounters a female alien named Mizuho Kazami. Little does he know just how significant to his life she will quickly become! It turns out that the alien is actually the new teacher at his school. Kei knows her secret identity though, and so she is forced to marry him in order to keep the truth about what she is a secret! But the story doesn't end there because it's not easy to be married, let alone married to an alien, and Onegai☆Teacher is a story of learning how to be in a relationship together.

Relationships are never easy, and Onegai☆Teacher shows that perfectly - with the added element of one party being an alien, of course. Like Asobi no Iku Yo!, the relationship between human and alien is strained at times due to very obvious cultural and behavioural differences on top of the factors that normally put stress on a relationship. Eris and Kio are able to work through their differences and still find their romance, and Kei and Mizuho do the same thing. Their relationship dynamic is a bit different with Mizuho being a teacher and Kei a student, but the struggles of being a human and an alien having a relationship is the same. If you liked Asobi no Iku Yo!, but also like teacher/student relationships, then Onegai☆Teacher will be perfect for you!

Rito Yuuki has always been too shy to confess his feelings to the girl he has a crush on, but that’s the least of his worries in To LOVE-Ru. One evening when he is enjoying his bath, suddenly a completely naked girl falls into his lap! It turns out she is Lala, an alien princess on the run of a politically motivated wedding. To avoid that wedding, she is happy to marry the overwhelmed Rito instead. But all Rito wants to do is still confess his love for his crush! Will he ever be able to do it, or will he be too tangled up with Lala (and the countless other alien girls that start to show up…) to have the opportunity?

To LOVE-Ru tells the story of a totally unexpected, but not unwanted, relationship between human and alien. Lala quite literally falls into Rito's life whether he wants it for not - but he doesn't exactly complain about her sexual advances and marriage proposal, either. Eris forces her way into Kio's life as well in Asobi no Iku Yo!, but he also doesn't put up much of a struggle. Besides how their relationship begins, there is another similarity between To LOVE-Ru and Asobi no Iku Yo! - both have alien girls with intense baggage they are bringing to the table.

Eris is trying to be captured by a lot of groups of people, and Kio has to do all he can to keep her safe. Lala has come to Earth in the first place to escape a political marriage and bad situation on her home planet, but her problems have followed her as well and pulled Rito into them. These unique issues that Rito and Kio have to deal with due to their alien girlfriends are the main thing that makes To LOVE-Ru like Asobi no Iku Yo!.

DearS begins with an alien ship crash landing in Japan. With no one able to fix the ship to return the aliens to their home world, the government of Japan decides to adopt them as Japanese citizens, dubbing their kind "DearS." However, clearly the aliens know nothing about Japanese culture! So to help them learn, they are put into a sort of "home stay" programme where they live with normal citizens to learn the language and how to survive in Japan. When Takeya Ikuhara rescues a female one, he ends up stuck with her whether he wanted to be or not! Dubbed Ren, the alien girl becomes attached to Takeya fast, even calling him her master! What will Takeya do with her now?

Much like Asobi no Iku Yo!, the alien girl that is the focus of DearS doesn't know a lot about human culture. Lucky for her, she has Takeya to teach her (however reluctantly at first). Eris originally came to earth to learn about the people living there, and Kio ends up being her unexpected teacher as well. Ren may not have forced herself into Takeyu's life on quite the level that Eris did to Kio, but Takeyu certainly didn't intend to host her when he saved her - and yet that's exactly what he ends up doing, much like Kio. Both relationships start with the girls being very reliant on the boys to understand the culture, and the boys being in a sudden care-giving role they never expected - and both result in romance! That transition in what their relationship was and what it becomes is what makes DearS a lot like Asobi no Iku Yo!.

Despite being an orphan, Yuuto Amakawa's life isn't so difficult - his biggest challenge in life is his intense cat allergy. Everything changes the day he turns sixteen in Omamori Himari when suddenly he starts being attacked by supernatural monsters called Ayakashi who want to punish him for his ancestors' sins! Lucky for Yuuto, he is saved by Himari, a mysterious catgirl. Up to age sixteen, he had been protected from the monsters by a charm, but now he had to learn to defend himself alongside Himari. Things just keep getting more complicated as he continues to be attacked, not to mention how many girls keep showing up wanting something or other from Yuuto...

The most obvious similarity between Omamori Himari and Asobi no Iku Yo! is the main heroine is a catgirl! Himari is not from another planet (probably) like Eris is, but they both have the distinctive cat ears that set them apart from other human characters. Both Himari and Eris stay with the male lead character most of the time as well, which develops into a romance. In Asobi no Iku Yo!, Kio is helping and protecting Eris, whereas in Omamori Himari the roles are reversed. Both are stories of partnership, though, with a male human and female catgirl helping one another overcome various obstacles. If you like an important catgirl in the story and a partnership where she has to work with a human, check out Omamori Himari!

What starts out as a normal day for first year high schooler Kaito Kirishima in Ano Natsu de Matteru will actually change his life - he just won't know it for a while. An amateur videographer, Kaito was out testing a new camera when he saw a mysterious blue light, and then blacked out without any memories other than waking up in his bed. Coincidentally, a new student named Ichika Takatsuki has now shown up at his school, and Kaito develops a crush on her. Little does he know just how much of a connection the two already have!

Ichika isn't just an ordinary girl who behaves a bit strangely; she's actually an alien, and when her ship crash-landed on Earth she accidentally fatally injured Kaito! Lucky for them both, she has the ability to replace his cells with her own that have healing nanomachines in them (of course by sharing a kiss) and saved him. So what does the future have in store for them now?

Like Asobi no Iku Yo!, Ano Natsu de Matteru is a love story between a high school boy, and an alien girl. While Ichika's appearance is not so obviously different like Eris', her actions and behaviour clearly mark her as different. As much as Ichika may try to behave as a human and check her mistakes, her oddities still do not go unnoticed. When she finally shares the truth about who she is with Kaito though, he doesn't mind at all that she is an alien and loves her anyway. Eris and Kio's relationship is also not affected by the reality that they are not from the same planet! Romance prevails all the same. So if you like the alien love story between high school aged characters who don't mind that they are not the same species that happens in Asobi no Iku Yo!, check out Ano Natsu de Matteru next!

Nyan Koi! is the ecchi of cat lovers' dreams. It's got fan-service, it's got a story, and of course, it's got cats! When high schooler Junpei Kousaka finds himself cursed by a cat deity and able to speak to cats, he has to do 100 good deeds for cats to break the curse and stop him from becoming a cat himself. It doesn't sound too hard - except that Junpei is deathly allergic to cats! And on top of that, his crush Kaede loves cats but is terrible at interacting with them. If Junpei is ever going to lift the curse, he's going to have to follow the advice of his family pet cat Nyamusas and his cat friends - if Junpei turns into a cat, he'll certainly die from his allergies!

Nyan Koi! may not have catgirls like Asobi ni Iku Yo!, but it does have cats, and girls. Lots of girls actually. Junpei may have a big crush on Kaede specifically, but his adventures to lift his curse bring him into contact with many other beautiful girls as well! And of course, Nyamusas and his many cat friends are always around Junpei whether he likes it or not, and they are always finding random cats to try to do 100 good deeds for. As mentioned earlier, if you like big-breasted girls and fanservice, and also like cats, Nyan Koi! is a great follow-up to Asobi ni Iku Yo!. It follows more of the cat theme than others on our list if the cats are your favourite part. Not to mention Nyan Koi! is also hilarious, too!