This study describes the development of a screening tool for gaming addiction in adolescents - the Gaming Addiction Identification Test (GAIT). Its development was based on the research literature on gaming and addiction. An expert panel comprising professional raters (n = 7), experiential adolescent raters (n = 10), and parent raters (n = 10) estimated the content validity of each item (I-CVI) as well as of the whole scale (S-CVI/Ave), and participated in a cognitive interview about the GAIT scale. The mean scores for both I-CVI and S-CVI/Ave ranged between 0.97 and 0.99 compared with the lowest recommended I-CVI value of 0.78 and the S-CVI/Ave value of 0.90. There were no sex differences and no differences between expert groups regarding ratings in content validity. No differences in the overall evaluation of the scale emerged in the cognitive interviews. Our conclusions were that GAIT showed good content validity in capturing gaming addiction. The GAIT needs further investigation into its psychometric properties of construct validity (convergent and divergent validity) and criterion-related validity, as well as its reliability in both clinical settings and in community settings with adolescents. © 2015 Scandinavian Psychological Associations and John Wiley & Sons Ltd.