BACKGROUND:the use of myofunctional therapy in cases of phonetic and/or phonological disorders. PROCEDURES: we included subjects being six and 13 year old, both genders, with phonetic and/or phonological disorders, and stomatognathic system alterations. We considered an exclusion criterion the presence of malformations, genetic syndromes, suspected neurological, psychological or cognitive impairment, hearing loss, diagnosis of language delay, speech therapy before, and malocclusion. Were held anamnesis, evaluation of the stomatognathic system, articulatory examination, hearing screening and othorrinolaringological evaluation. We held two therapy weekly. Surveys were carried out every eight sections. We analyzed the comparison between the number of speech sounds and features/structures of the stomatognathic system alterations before and after such therapy, and also the comparison between subjects in relation to length of therapy according to the found speech disorder. RESULTS: the subjects with phonological disorder showed between one and four alerted phonemes, the subjects with a phonetic deviation showed one altered phoneme, but the subjects with a phonetic-phonological deviation had five to six altered phones/phonemes, respectively. The cases of phonological and phonetic deviation had proper speech. One of the subjects with a phonetic-phonological deviation had proper speech, and the other showed an altered phone. CONCLUSION: myofunctional therapy was efficient in cases of phonetic and/or phonological deviations.