Officials say the gun accidently fired when it fell from the 6-year-old boy's pocket as he sat down for lunch Tuesday. The boy and two other students were wounded.
Some parents said the incident has made them think twice about safety at Ross Elementary School. They wonder if additional security measures, including extra officers and metal detectors, are needed.
School district officials said extra security will be in place Wednesday to allay parents' fears.
Houston police spokesman Victor Senties says it's too early in the investigation to tell if any charges will be filed.