The Giver is one of my all time favorite novels to teach at the middle school level. I have personally taught it with both advanced 6th graders and with regular 7th graders. I would not recommend teaching it any lower than this because the students are unable to comprehend the complexities of the community, the act of giving and receiving memories, and the incredible sense of betrayal that Jonas feels.
When teaching it with both grades, I incorporated a photo journalism project that started with black and white pictures, and then evolved into color. I even played with the digital images promoting red and subduing the other colors. This had a profound impact on the students since they were able to see the world through Jonas's eyes.
This is a incredible novel and provokes some wonderful discussions.
Hope this helps,
Many teachers teach Lowry's The Giver in grades 7 and 8 (intermediate level). However, as a department head, I, as well as my teachers, decided to teach it in our grade 9 English classes (junior?). Although the level of difficulty with regards to reading the novel is not very difficult, teaching this novel in the context of a grade 9 class will allow the teacher to explore the themes much more profoundly. Students at this age are a little more mature and are more prepared to discuss and to understand some of the complex issues presented in the novel. This will allow for such discussions as euthanasia, utopia, communism... and so much more.