David Herman, 25, of Seguin, Texas, died at the scene of the wreck, which occurred about 12:20 a.m. near Antlers, the patrol said.
Herman was driving the ATV on a rural county road when he failed to negotiate a curve, the patrol said.
The ATV veered off the road and struck a tree.
His passenger, Andrea D. Songer, 34, of Antlers was flown to OU Medical Center in Oklahoma City in critical condition, the patrol said.
Neither Herman nor Songer was wearing a helmet.
