An apparatus for warning of dangerous passing of a vehicle may include: a vehicle information collector configured to collect vehicle information containing one or more of vehicle speed, traveling direction, and location; a vehicle information transmitter/receiver configured to transmit the vehicle information collected through the vehicle information collector, and receive other vehicle information transmitted from other vehicles; a controller configured to determine the direction of a lane change signal when the lane change signal is inputted, and determine whether to output a warning based on the vehicle information collected through the vehicle information collector and the other vehicle information received through the vehicle information transmitter/receiver; and a warning output unit configured to output a warning according to the determination of the controller.