Dickinson ISD said in a Facebook post Wednesday evening that the student was arrested by Galveston County sheriff's deputies after two students reported the threat to school officials.
"I'm going to kill everyone," the student allegedly told another student, prompting a call to deputies.
The district said the student will not be permitted to return to the school.
Wednesday's arrest comes on the heels of another threat at Dunbar Middle School on Tuesday. Administrators said their investigation continues in that incident.
School officials said they take each threat allegation seriously, and that students "must understand that their words and writing, whether they are serious or joking, have the power to incite fear in others."