The children had been told to bring important family items to class at the Sweet Springs school, and school officials called police when the child produced the pipe and several baggies of drugs from his backpack, KCTV, Kansas City, reported Monday.
Police said the child's mother, Michelle Marie Cheatham, 32, has been charged with possession of a controlled substance and one count of first-degree child endangerment.
Police Chief Richard Downing said a child bringing drugs to show-and-tell was a first in his law enforcement career.
"When I called the prosecutor about it, they said, 'You're kidding me, aren't you?'"
The boy is now being cared for by family members, a family friend told KCTV.