Gokujou Seitokai

Both are set in a high school where the females hold special fighting abilities. Mai-Hime is more magical and contains more serious drama.  

Both feature an enormously overpowered student council.  

They are both in school based and quite funny with adorable characters ^_^ 

Gakuen Heaven is an all boys school that has someone who is normal transferred into the school because the chairman (or president) either knows or is familiar with that person. Even though it is a boy love anime it is basically the same thing with Gokujou Seitokai but with girls. If you liked Gokujou Seitokai (and don't mind a bit of shounen-ai) then you will like Gakuen Heaven and vice versa. Both are very funny with nice endings! 

Very character-based series. Both Mahoraba and Gokujou Seitokai uses the main character and a loose storyline to take the viewer through the lives of the side characters in great depth. Similar type of no-frills, simple artwork and animation, both are fairly light-hearted (for the most part) series. 

Both have a main character that happens to be a puppet or in Midoris case half of her is on her crushes right arm. If you like the wise cracking Pu-Chan; then you'll enjoy Midori and her never ending quest to express her love.  

Both series are school-related and have one or more characters with an extraordinary power. While both are also placed in the comedy category, there is a hint of tragedy in both as well. 

Both revolves around school. They are both cute, crazy animes.These animes are suitable for all ages .And believe me watching both anime will be a great experience. Ouran revolves more around school boys and one girl(dressed as a boy) Gokujou Seitokai has several tomboys who govern over their school (There is also a mad puppet in this anime). They do several exciting and funny things.The story is simple and crazy... not serious type 

When I was watching Gokujou Seitokia it slightly reminded me of Kokoro Toshokan. All the adventures the girls had in the episodes and also Kokoro and Rino never gave up. In both series the characters protect what is important to them, the Kokoro Library and the Miyagaki High School. 

Best Student Council has a more interlaced backstory, but it shares a common base concept with Manabi Straight!: New transfer student gets into student council, and overall mission is to make the students happy to be at school. 

both about a girl going to new school and both have comedy/romance and both got some good shouj-ai. 

both arecomedies with lots of characters thatgrow on you more as the episodes progress and both are a little weird at times whichkeeps it iinteresting. 

Not really similiar in a sense, but there are a few things that are the same. In Gokujou Seitokai there is an essence of magic, also the presence of an almighty student council is in both of them. Not sure what it was that made me feel like they were the same, think its basicaly just the student council bit. 

Both series have a group of students superior to the rest. Both also have enjoyable characters that can make you laugh out loud or tear up.