An image classification apparatus and method for Automatic White Balance (AWB) are provided. An input image is divided into blocks including pluralities of pixels. A hue value and a chroma value are calculated for each of the blocks. A color-changed block is detected by calculating, for each one of the blocks, differences between the hue and chroma values calculated for all blocks adjacent to the one of the blocks and the hue and chroma values calculated for the one of the blocks. A hue variance and a chroma variance are calculated for the entire input image if a number of the detected color-changed blocks is greater than or equal to a first threshold. The input image is determined as a non-monochromatic image, if the hue variance is greater than or equal to a second threshold or the chroma variance is greater than or equal to a third threshold.