When her class was on a trip to the bathroom, the little girl said she got left behind.
She says she couldn't find her way back to class, so she left from Law Elementary's front gate and took the 10-minute walk alone.
Her mom, Ashley Palms, took her back to the school.
She told ABC7's sister station, ABC13, she was outraged, and said administrators showed her surveillance video of Alyssa walking out.
"You could see in the video how scared she was," said Palms. "She sat down and kind of started hugging her own legs and looking around, and just confused and not knowing what to do."
She said the principal had just learned Alyssa was missing because a stranger spotted her walking and told the front office.
"The moment the bystander outside noticed my daughter was walking down the street and she alerted the school, I feel like they should have been put on lockdown somehow," Palms said.
The school district sent ABC13 the following statement regarding the incident:
"The district is looking into this matter to determine what occurred and how best to ensure the safety of all HISD students. In addition, the campus is reviewing its procedures to ensure that all children are properly supervised, as the safety of our students is always our top priority."
Palms hopes this is a lesson learned for the school, and says she's thankful it didn't end up much worse.
"She could have been kidnapped, abducted anything could have happened," Palms said.