This was actually a really difficult list to compile; I have too many favorites, but I will share some of the ones I know were very popular with my 4th graders when I taught school. There will be other lists to share other great reads for middle grade (4th-6th grade mostly.)
1. Harry Potter & the Sorcerer's Stone
by: J.K. Rowling
I mean, all I have to say is this is one of the best renditions of the magic & wizarding world you will ever read! Hogwarts is my ideal place to attend school & I would totally sign up to play Quidditch! Harry Potter is an endearing, resilient protagonist who makes some wizard friends (Ron & Hermoine) & I'll be surprised if you don't pick up every book in this series!
*Recommended grade levels: 5-6
2. The Mysterious Benedict Society
by: Trenton Lee Stewart
A group of 4 unlikely friends gets banded together after a series of strange tests (both written & actual challenges.) These friends are actually quite gifted children, but they don't exactly know what they can accomplish until they're under pressure, working together. They are sent as spies (yes, the children!) to a boarding school where they seek to uncover some secret workings of a Ledroptha Curtain. It's a page turner!
*Recommended grade levels: 6-8
Interest Level: 4-8 (keep this in mind if you'd like to read the story aloud to your kids or students.)
by: R.J. Palacio
This heartwarming story was actually made into a movie last year. It's an excellent book to read with your students or kids to help them empathize with kids who might look or act differently than them. Wonder is about a boy named Auggie who had to undergo some pretty serious surgeries as a young kid that altered his face; many kids are rude to him and taunt/bully him once he starts going to public school. (His mom home-schooled him until 5th grade because of his medical issues & appearance.) It's a very relatable & emotional story about the importance of acceptance & love.
*Recommended grade levels: 4-6
4. The Indian in the Cupboard
by: Lynne Reid Banks
This one's a classic for everyone with an imagination! Omri is a boy who is gifted an old cabinet from his brother for his birthday, & with the turn of a magical key, he's able to bring not only an Indian, but also many soldiers and cowboys to life. He has his own little world to run!
*Recommended grade levels: 4- 5
by: Roald Dahl
I had to include at least one book by Dahl; his works are also perfect for this age group. Matilda comes from an unexciting home, where her imagination, wit & smarts become the tools she is able to compete with. Mrs. Honey seeks to take good care of this sweet, intelligent girl after having her as a student in her class.
*Recommended grade levels: 2-4