The primary purpose of this current study was to identify knowledge of special education and mental health professionals in anxiety-related problems of children with autism spectrum disorder (ASD) in four Different Categories: Separation Anxiety (SA), Uncertainty (U), Performance Anxiety (PA), and anxiety Arousal (AA). Three hundred eighteen participants across the United States (199 special education teachers, 97 school counselors, and 22 school psychologists) participated. The finding indicated that special education teachers and school counselors have significantly less training and expertise to identify anxiety symptoms in typically developing children and children with ASD than school psychologists (p < 0.05). Moreover, school counselors have significantly limited knowledge in identifying and treating anxiety issues in children with ASD (p < 0.05). Findings showed that school counselors could not determine precisely whether symptoms of uncertainty events existed because of anxiety issues or ASD characteristics. School psychologists and special education teachers identified the uncertainty of children with ASD as characteristics of children with ASD, not anxiety symptoms. Implications were discussed.