Clayton Whatley was charged with unlawfully carrying a weapon, according to jail records.
The accidental shooting happened at 7:40 p.m. at the College of the Mainland Law Enforcement Training Academy on 1200 Amburn.
Texas City police say cadet Whatley had a loaded handgun in his backpack.
During class, Whatley reached into his bag and the handgun fired, hitting two cadets in their calves.
A third cadet was grazed.
The two cadets who were shot, a man and a woman, were transported to UTMB with non life-threatening injuries.