An object orientation determination method includes generating pixel data on each of a plurality of unit pixels included in a region of interest of a point cloud acquired from an object, generating a plurality of candidate boxes using the generated pixel data, and determining, as a heading angle of an oriented bounding box, an inclination of a candidate box having a smallest cost among costs calculated on the plurality of candidate boxes. A cost of each of the plurality of candidate boxes is calculated based on positions of respective sides of a corresponding one of the plurality of candidate boxes and the pixel data.