Objective: The purpose of this article is to introduce a new assessment designed to measure the orofacial abilities of children who stutter (CWS), the Movement, Articulation, Mandibular and Sensory Awareness (MAMS) Orofacial Assessment. The new instrument was developed and validated to measure orofacial abilities in a comprehensive manner. Design: A group of 43 CWS (mean age 13.10 years, S.D. 2.10 years) and a control group of 32 fluent children (mean age 13.4 years, S.D. 2.6 years) were tested with the new tool. It was hypothesized, that (a) the MAMS is a reliable and valid instrument to measure orofacial abilities in CWS, (b) fluent children have better orofacial abilities than CWS and (c) that the therapy outcome of CWS depend on their orofacial abilities. Results: The MAMS Orofacial Assessment proved to be a valid and reliable instrument to assess orofacial abilities. Compared with their fluent peers, CWS had significantly worse orofacial abilities. CWS with better orofacial abilities had a better prognosis for therapy outcome. Conclusions: The new instrument is a reliable and valid tool to measure orofacial abilities and MAMS distinguishes CWS and controls. Orofacial abilities are one set of factors that influence therapy outcome for CWS. Educational objectives: The reader will get an overview over of the literature on orofacial abilities in people who stutter and will learn about and be able to (1) describe different characteristics of orofacial abilities, (2) use the MAMS Orofacial Assessment in the diagnostic process for CWS and for research purposes, and (3) interpret the results of the MAMS to use them for therapy planning.