To develop and validate the Problematic and Risky Internet Use Screening Scale (PRIUSS)-3 screening scale, a short scale to screen for Problematic Internet Use.This scale development study applied standard processes using separate samples for training and testing datasets. We recruited participants from schools and colleges in 6 states and 2 countries. We selected 3 initial versions of a PRIUSS-3 using correlation to the PRIUSS-18 score. We evaluated these 3 potential screening scales for conceptual coherence, factor loading, sensitivity, and specificity. We selected a 3-item screening tool and evaluated it in 2 separate testing sets using receiver operating curves.Our study sample included 1079 adolescents and young adults. The PRIUSS-3 included items addressing anxiety when away from the Internet, loss of motivation when on the Internet, and feelings of withdrawal when away from the Internet. This screening scale had a sensitivity of 100% and specificity of 69%. A score of ≥3 on the PRIUSS-3 was the threshold to follow up with the PRIUSS-18.Similar to other clinical screening tools, the PRIUSS-3 can be administered quickly in a clinical or research setting. Positive screens should be followed by administering the full PRIUSS-18. Given the pervasive presence of the Internet in youth's lives, screening and counseling for Problematic Internet Use can be facilitated by use of this validated screening tool.