Turned into a Girl at Claregrove

The vast majority of the books where a guy ends up as a real girl are in the category of forced feminization. They get turned into girls whether or not they want to. The stories are also often heavily sexual.

This one avoids those problems. Steven is an orphan who moves in with his sister who is a teacher at Claregrove which is a girl's academy. He's very lonely and is told to stay away from the girls, being educated at his new home.

Eventually, though, he is given permission to join a couple of the clubs for the girls but with the stipulation that he must obey all the rules and that includes wearing the proper girl outfits. The book goes into all of this and how the girls react to him and how he reacts to wearing girls' clothes and basically acting like a girl for most of the day.

It's a very wonderful story that, fortunately, has a happy ending.