An image processing device including a decoding section configured to decode an image from an encoded stream, a determination section configured to perform determination processes of determining whether to apply a deblocking filter to neighboring blocks neighboring across a block boundary within an image to be decoded by the decoding section, a filtering section configured to apply a deblocking filter to neighboring blocks to which the determination section has determined to apply a deblocking filter, and a control section configured to allow the determination section to perform the determination processes for a vertical block boundary and a horizontal block boundary using pixels of the neighboring blocks of a reconstruct image as reference pixels.