School nurses may be the first health professionals to assess the onset of facial paralysis/muscle weakness in school-age children. The purpose of this study was to test the psychometric properties of the Gordon Facial Muscle Weakness Assessment Tool (GFMWT) developed by Gordon. Data were collected in two phases. In Phase 1, 4 content experts independently rated each of the 22 items on the GFMWT for content relevance. The ratings were used to generate Item and Scale Content Validity Index (CVI) scores. In Phase 2, school nurses (N = 74) attending a state conference independently rated referral urgency on a set of 10 clinical scenarios using the GFMWT. The GFMWT had an item and scale CVI of 1.0. Overall, the interrater reliability was 0.602 (p less than 0.001). When used by school nurses, the GFMWT was shown to be both a reliable and a valid tool to assess facial muscle weakness in school-age children. (Contains 2 figures and 4 tables.)