Houston Police said it happened on Edgemoor just south of Bellaire in Sharpstown.
According to HPD, when the 4- and 5-year-old children and their mother returned home, the woman's ex-boyfriend was waiting for them.
The mother and her ex-boyfriend got into a physical altercation, police said. At some point, the woman's current boyfriend also got involved.
During the fight, the ex-boyfriend reportedly got into the woman's car -- with the children still inside -- and drove off.
"The suspect was actively texting a person that the complainant knew. So we knew that he had kids in his custody. At that point, he was trying to find a location where he could return the kids, but not have police presence," Lt. F. Croft said.
A police helicopter spotted the man driving the stolen car. Officers tracked the suspect down and arrested him.
The kids were found in the vehicle and were not harmed, HPD said.
Police said the children have no relation to the ex-boyfriend who is accused of taking them.