Disclosed is a method and apparatus for determining a lane, the method including extracting plural straight-line segments from a captured stereo image including a first image and a second image of a driving road, selecting a first lane from the stereo image based on line segments of the plural straight-line segments, corresponding to lanes of the driving road, predicting a second lane candidate, based on the first lane, including at least a portion of a lane area excluding the line segments in the stereo image, and determining a second lane by updating a position of the predicted second lane candidate based on a confidence value of the predicted second lane candidate.