The current study investigated the contribution of two linguistic intervention programs, phonological and morphological to the development of word spelling among skilled and poor native Arabic readers, in three grades: second, fourth and sixth. The participants were assigned to three experimental groups: morphological intervention, phonological intervention and a non-intervention control group. Phonological awareness, morphological awareness, and spelling abilities were tested before and after the intervention. Participants from both linguistic intervention programs and in all grades made significant progress in linguistic awareness and spelling after the intervention. The results showed that both intervention programs were successful in promoting children's spelling skills in both groups. Also, older poor readers showed a stronger response to the morphological intervention than the older skilled readers. A transfer effect was found with the phonological training contributing to the morphological skills and vice versa. The results of the current study were discussed in the light of developmental and psycholinguistic views of spelling acquisition as well as the characteristics of Arabic language and orthography.