The suspect was arrested almost 30 minutes after the 8 a.m. incident at Abilene High School, police spokesman Rick Tomlin told KTXS-TV
Both victims were rushed to Hendrick Medical Center and their conditions are unknown.
Police said the attack appeared to be targeted and a result of a “previous altercation” between at least one of the victims and the suspect, Tomlin said.
“He showed up here this morning, apparently, directly targeting the two victims,” he said.
All three of the male students involved in the incident are minors and are "around 16" years old, police said.
The stabbing happened right outside the school's cafeteria and there was an increased police presence on campus following the attack.
The Associated Press contributed to this report.