Objective: The current study sought to develop a culturally appropriate measure of functional impairment related to ADHD for diverse families, as research suggests that functional impairment may be a more culturally universal construct than symptomatology. Method: Seventy-four low-acculturated Latino parents (49 mothers and 25 fathers) of school-aged children provided quantitative and qualitative responses about problem recognition after viewing a language-free video of a child displaying symptoms and behaviors consistent with ADHD. Results: Thirty-two items were developed for the ADHD-FX scale based on most common responses given from participants. The scale is available in Spanish and English and instructs parents to consider how much each item affects their child in his or her everyday life (from 0 = not at all to 3 = a lot). Conclusions: The scale can provide an overall impairment score, as well as subscale scores in the theoretically derived domains of academic, peer, and familial impairment.