Ore no Imouto ga Konnani Kawaii Wake ga Nai, Himouto! Umaru-chan Recommendations
Both series has a Brother and sister setting. Both main heroine are Prodigy of their school (Doma Umaru and Kousaka Kirino) but inside they are actually an Otaku, and the only person who knows is their brother (Doma Taihei and Kousaka Kyousuke).
I don't really like Kirino's personality toward his brother, but its a great series which I can compare to Himouto! Umaru-chan. Recommended for Comedy fans!
Both female protagonists are popular, beautiful, and charming high school girls. But are actually closet otakus, devoting their lifestyle to it. Both have tsundere tendencies towards their older brother, while at the same time bonding over activities such a video games. Both also have diverse groups of friends who have to struggle maintaining their home and school life with.
Basically about a perfect imouto on the outside but is in reality a shut-in. It follows the daily lives of them trying to hide their identity. OreImo however does have a side plot, with a much wider cast. Both of them has a storyline and connection, yes, even Umaru-chan has it. Also the imoutos are annoying in both series. Finally, there's a sub genre of romance although again, in OreImo it completely takes over.
OreImo has better storyline but Umaru-Chan has better comedy and SoL elements.
If you are sister-con, you will enjoy Oreimo and Umaru-chan, as both series have a younger sister and an elder brother as main characters.
Kirino and Umaru, the heroines of two series, are both perfect top students at school but actually otakus at home, while only their brothers, Kyosuke and Taihei, know their true sides. If you are an otaku like Kirino and Umaru, you may have the same feeling as them and enjoy the comedies about their daily life with their friends.
The anime are both slice of life comedies focused around the relationship between the main character and his younger sister. Both of the sisters act like perfect girls at school but are secretly otakus at home. OreImo is more plot heavy and has romance in it while Umaru-chan is mostly slice of life. If you like lighthearted comedies and anime focusing on little sisters you'll probably like both of them.
Both have to do with an older brother taking care of a younger one, just one doesn't have sibling romance.
Umaru is a bit more animated in terms of expressions of the characters. Storylines are not very similar at all, but if you like sibling anime, then you'll probably like this one.
little sister being a jerk and plain big bro helping her for no reason