Previous research has mostly correlated screen time with adolescents’ social, cognitive, and emotional well-being outcomes, while overlooking adolescents’ subjective experiences of smartphone use. The present research filled this gap by developing and validating the Perceived Digital Well-Being in Adolescence Scale (PDWBA). This semantic differential scale was developed by conducting a literature review and five cognitive interviews with Slovenian adolescents and then tested in two cross-sectional studies. A total of 161 Slovenian adolescents participated in Study 1 (Mage = 17.87, SDage = 1.23), and 1,040 Slovenian adolescents (Mage = 15.28, SDage = 1.79) participated in Study 2. Exploratory and confirmatory factor analyses demonstrated a stable three-factor model consisting of perceived digital well-being subscales in the social, cognitive, and emotional domains. Construct validity tests were performed and metric invariance across sex was established. The descriptive results showed that adolescents’ perceived digital well-being differed according to sex, age, and educational track. We discuss the scale’s theoretical and practical relevance and formulate suggestions for future research.