Students in the Broward County (Fla.) district will be allowed to use only clear backpacks and bookbags beginning next school year.
NBC 6 Miami reports that the policy will go into effect on Aug. 21 for students in all grades from pre-K to 12th.
The rule does not apply to teachers, staff, volunteers or visitors.
District officials say the policy is intended to bolster campus security.
"Providing safe learning environments that are conducive to student learning is of the highest importance, not just for Broward County Public Schools but for school districts across the nation," says Interim Superintendent Earlean C. Smiley.
"This added layer of security is a game-changer. It will allow school security personnel and everyone on campus to quickly spot and report if someone has brought a prohibited item to school, and it will also help serve as a deterrent."
The policy also applies to lunch boxes, purses, duffel bags and fanny packs. Mesh and colored backpacks, even if transparent, are also banned.
Exceptions will be made for a small non-transparent pouch for personal hygiene items, thermal food containers carried inside clear lunch boxes, school-approved sport-specific carrying cases for athletic equipment and school-approved instrument-specific carrying cases for band equipment.
Broward County is the nation's sixth-largest public school system in the country with more than 250,000 students.