Provided are a pixel processing apparatus, and an image signal processing apparatus and an image processing system each including the same. The pixel processing apparatus includes a bad pixel processing unit configured to determine whether a target pixel is a bad pixel based on pixel data of an image sensor, output a bad pixel detection signal according to a result of determining whether the target pixel is a bad pixel, compensate for a pixel value of the target pixel based on the pixel data, and output the compensated pixel value; and a noise removal unit configured to remove noise from the pixel value of the target pixel, based on the bad pixel detection signal, the pixel value, the compensated pixel value, and weight information.