ABSTRACT Purpose to evaluate the efficacy of orofacial myofunctional therapy in improving orofacial function and nasal breathing in patients with asthma and rhinitis and, consequently, achieve clinical control of these conditions. Research strategies We used the elements of the PICOT method (study population, intervention, comparison, outcomes and type of studies) to define the eligibility criteria: (1) Population: patients with asthma and rhinitis; (2) Intervention: orofacial myofunctional therapy to improve chewing, swallowing, and breathing; (3) Comparison: control group without orofacial myofunctional therapy; (4) Predefined outcomes: clinical control of asthma and improvement of orofacial functions and nasal breathing; (5) Study type: clinical trials. The data were collected from PubMed, SCOPUS, Web of Science, Science Direct, LILACS, Google Scholar, Cochrane Central Register of Controlled Trials (CENTRAL), OATD, and Open Thesis, in November 2018. Selection criteria Randomized controlled trials published in full-text versions without language restriction, no filter was used. Data analysis Demographic characteristics of study participants, specific diagnosis of asthma and control medication, type, duration, intensity and follow-up of orofacial myofunctional therapy, and outcome data. The risk of bias was assessed according to the Cochrane guidelines for clinical trials. Results One study met the eligibility criteria: although the study has shown an improvement of functional control and clinical scores of asthma, the evidence is very low. Conclusion There is no scientific evidence on the efficacy of orofacial myofunctional therapy in improving clinical control, orofacial function, and nasal breathing in patients with asthma and rhinitis.