Technically, JRR Tolkien wrote The Lord of the Rings as a sequel to The Hobbit. However, while The Hobbit is a great story for upper-elementary-aged children, The Lord of the Rings is a darker story, much more intense and scary.
And like The Hobbit, learning how to read The Lord of the Rings will greatly increase your enjoyment of it. (See my hints on reading Tolkien here.)
Yes, the movies are good. I actually like the movies enough that I watch them about once a year (unheard of for me!).
But I like the books even better. As good as the movies are, they cannot fully relate the exhaustion of the journey, the friendship between the hobbits, Gandalf, Gimli, Aragorn, and Legolas, among the many other intricacies of the books.
As with The Hobbit, you can listen to an unabridged version of The Lord of the Rings. It will take a long time, but it’s worth it.
I will admit, I am not a huge fan of fantasy, but I love these books.
Highly recommended for ages 13 and up.