The present disclosure relates to a signal processing device and an image display apparatus including the same. A signal processing device according to an embodiment of the present disclosure includes: an input interface to receive an image signal; a first image processor to generate first image frame data based on the image signal; a second image processor to generate second image frame data scaled down from the first image frame data based on the image signal; and an output interface to receive the first image frame data from the first image processor and the second image frame data from the second image processor and to output the first image frame data and the second image frame data, wherein the first image frame data output from the output interface is more delayed than the second image frame data output from the output interface. Accordingly, a timing controller may accurately and rapidly perform signal processing for a panel.