Visual-perceptual and spatial-relationship deficits affect deaf children’s ability to communicate and to understand a message when spoken or signed. Children with these perceptual deficits cannot distinguish moving or changing oral shapes when lip reading. They have serious problems differentiating each finger from the whole hand and perceiving how a speaker’s fingers are positioned when facing them. Therefore, they have difficulty learning to use sign language and reading the message conveyed by sign. Visual-spatial-perceptual deficits occurring in deaf children seriously delay and impair language development and social development. Every academic area is affected. Specific problems are described, and the effect of the deficit on academic performance is discussed.