An apparatus configured for determining an intention to cut in in a vehicle may include a navigation module, a camera, a radar configured to obtain data about an external vehicle, a sensor configured to obtain data about behavior of the vehicle, and a processor configured to be electrically connected to the navigation module, the camera, the radar, and the sensor, wherein the processor is configured to obtain information associated with at least a portion of a road environment, traffic, or road curvature based on data obtained using at least a portion of the navigation module, the camera, the radar, or the sensor and adjust a parameter for determining an intention for a surrounding vehicle which is traveling in a second lane adjacent to a first lane where the vehicle is traveling to cut in, based on the obtained information.