An embodiment vibration motor assembly of a seat includes a vibration motor and an upper housing disposed around the vibration motor to hold and fix the vibration motor, the upper housing configured to be fixed to a pad of the seat, and the upper housing including a holding part disposed at a circumference of a front surface of the upper housing to hold a circumference of the vibration motor and a fixing part protruding from a rear surface of the upper housing to cover and fix a rear surface of the vibration motor.