Purpose: The purpose of this systematic review was to examine the current evidence for the use of oral motor exercises (OMEs) on speech (i.e., speech physiology, speech production, and functional speech outcomes) as a means of supporting further research and clinicians' use of evidence-based practice. Method: The peer-reviewed literature from 1960 to 2007 was searched for articles examining the use of OMEs to affect speech physiology, production, or functional outcomes (i.e., intelligibility). Articles that met selection criteria were appraised by 2 reviewers and vetted by a 3rd for methodological quality, then characterized as efficacy or exploratory studies. Results: Fifteen studies met inclusion criteria; of these, 8 included data relevant to the effects of OMEs on speech physiology, 8 on speech production, and 8 on functional speech outcomes. Considerable variation was noted in the participants, interventions, and treatment schedules. The critical appraisals identified significant weaknesses in almost all studies. Conclusions: Insufficient evidence to support or refute the use of OMEs to produce effects on speech was found in the research literature. Discussion is largely confined to a consideration of the need for more well-designed studies using well-described participant groups and alternative bases for evidence-based practice. (Contains 1 figure and 7 tables.)