Temple

Both stories revolve around a guy who is deeply focused on his studies and, due to certain circumstances, ends up living in a temple with girls his age who eventually start falling for him. While the themes are very similar, the way each story unfolds makes them feel somewhat different, especially in terms of the characters. Still, the similarities are quite noticeable. 

Male MC staying in a temple, 3 shrine maiden sisters, flavored with romance comedy and a little bit ecchi scene due to misunderstanding 

The basic premise is the same - guy spends time with 3 sisters at a religious institution. There's also this subplot about saving that place. Differences: Temple: A son of a womanizer decides to break the mold and go to a Zen Buddhist temple to achieve nirvana, unaware that 3 beautiful sisters inhabit it, along with 2 foreigners and an abbess. Amagami Sister: A non-believer goes to Kyoto to study, but gets roped in by a Shinto shrine elder, who tells him to marry one of his granddaughters in order to save his shrine. Guy also has some time with his folks at his childhood orphanage. Another major difference is that Temple is a lewd and funny seinen story while Amagami Sister is a feel-good mythic rom-com for the shonen demographic. read more 

These 2 has the exact same story, guy going to a Temple full of girls to become a monk. There he becomes overwhelmed surrounded by the beauties of the world. But can he suppress his worldly temptations.  

both are Harem Ecchi Comedy genre And the MC lives with beautiful Girls,But the majour difference is Yuragi-sou no Yunna-san is supernatural (there are spirits and ,magical powers). Instead of the temple its a Hot springs inn in Yuragi-sou.... The MCs of both Anime is accused as pervets by other girls and fathers of both of them go to buy milk.  

Watched the first episode of Temple and thought the comedy style was similar to Grand Blue. Only on MAL I discovered they're actually from the same author as well.