Oniichan wa Oshimai!

Onimai: I'm Now Your Sister!

What would you like to edit?

Alternative Titles

Synonyms: Onimai, Onii-chan is Done For
Japanese: お兄ちゃんはおしまい!
English: Onimai: I'm Now Your Sister!
More titles


Type: TV
Episodes: 12
Status: Finished Airing
Aired: Jan 5, 2023 to Mar 23, 2023
Premiered: Winter 2023
Broadcast: Thursdays at 23:30 (JST)
Licensors: None found, add some
Studios: Studio Bind
Source: Manga
Genre: ComedyComedy
Themes: CGDCTCGDCT, Magical Sex ShiftMagical Sex Shift, SchoolSchool
Demographic: ShounenShounen
Duration: 23 min. per ep.
Rating: PG-13 - Teens 13 or older


Score: 7.671 (scored by 7096770,967 users)
1 indicates a weighted score.
Ranked: #13162
2 based on the top anime page. Please note that 'Not yet aired' and 'R18+' titles are excluded.
Popularity: #1557
Members: 148,767
Favorites: 2,106

Available At


Streaming Platforms

Ranked #1316Popularity #1557Members 148,767
Add to My List
Episodes: /12


Self-professed "home security guard" Mahiro Oyama has not left his home in years, secluding himself in his room playing erotic visual novels. This depraved lifestyle causes his prodigious sister, Mihari, to worry about his well-being. In hopes of solving this problem, she devises a plan to rehabilitate him back to normalcy.

The first part of Mihari's plan is to concoct a medicine that changes her brother's biological constitution into a bona fide female, much to Mahiro's vehement dismay. Stuck in this predicament, Mahiro has no choice but to live out his life as a cute girl until the effect wears off—if it ever does.

[Written by MAL Rewrite]


Oniichan wa Oshimai! was released on Blu-ray in two boxes from April 19, 2023, to June 21, 2023.

Characters & Voice Actors

Murosaki, Miyo

Hioka, Natsumi

Fujimi, Nemu

Sakurai, Mia


Uchida, Yuuya

Nagase, Miyako

Oda, Karin

Kitahara, Yuriko

Nagae, Rika


Hishiyama, Mitsuteru
Higashi, Mao
Assistant Producer


Opening Theme

Apple Music
Amazon Music
Youtube Music
"Iden Tei Tei Meltdown (アイデン貞貞メルトダウン)" by Enako feat. P-maru-sama. (P丸様。)

Episode Videos


Mar 23, 2023
Like many, I was impressed with the debut of Studio Bind and their highly-anticipated, highly-praised, highly-controversial anime adaptation for Mushoku Tensei: Jobless Reincarnation, and like so many more, I was already getting excited for its second season as soon as its first came to a close. However, also like many, I proceeded to be half-disappointed, half-confused when I saw the announcement for Oniichan wa Oshimai! with the name of Studio Bind—the studio which I thought was created for the sole purpose of adapting Mushoku Tensei—so proudly attached. A veteran animator like Shingo Fuji making a directorial debut at a studio I can actually trust to ...
Mar 23, 2023
Mixed Feelings
The only reason why I decided to give this anime a shot is because of the fact it was going to be animated by Studio Bind. Therefore, I thought... "Why not? Looks interesting to me. A gender-bender anime about a failure in life who became a loli by his or should we say 'HER' now to give HER a second chance in life." Now I know what you're thinking, if you look into this out of context, it's essentially a story about a fully grown man who's living alongside middle schoolers who don't have the slightest idea of this PERSON's past, yet it's treating it ...
Dec 11, 2023
The premise is from the get-go that a man (older brother, true gamer nerd/enthusiast, recluse but ultimately harmless) wakes up having been turned into what looks like a pre-teen girl by his "mad scientist" sister, via a drug. In her room she has a manual on her desk which deetails how she wants to turn him into her little sister, meaning this is entirely deliberate with an agenda.

It SOUNDS like this should be a hilarious comedy to give a guy what he deserves in order to appreciate what being a girl or a woman is like, as punishment.
That's not at all what it is. ...

Interest Stacks

50 Entries · 8 Restacks
by ellps
28 Entries · 26 Restacks


Recent News

Winter 2023 Simulcast List [Update 1/26]

Winter 2023 Simulcast List [Update 1/26]

In this thread, you'll find a comprehensive list of television anime acquired for simulcast release during the Winter 2023 season. Anime series licensed for hom...read more

Winter 2023 Preview

Winter 2023 Preview

In this thread, you'll find a comprehensive list of Winter 2023 titles with an accompanying promotional video, commercial, teaser, or trailer. This post will be...read more

Recent Forum Discussion

Poll: Oniichan wa Oshimai! Episode 2 Discussion ( 1 2 3 4 )
Stark700 - Jan 12, 2023
195 repliesby RaptorDan »»
May 17, 1:20 PM
Poll: Oniichan wa Oshimai! Episode 8 Discussion ( 1 2 3 )
Stark700 - Feb 23, 2023
124 repliesby Juicedi »»
Apr 25, 1:54 PM
I love Asahi!
BigBoyAdvance - Feb 7
20 repliesby Zarutaku »»
Apr 23, 3:19 PM
Poll: did this show get you excited
weeaboo5008 - Dec 26, 2023
31 repliesby Zarutaku »»
Apr 23, 2:07 PM
Poll: Who do you like the most? (Favorite/best girl poll)
Onii-chanShuki - Mar 18, 2023
31 repliesby rin750 »»
Mar 20, 1:22 AM