This study aims to develop the Online Pornography Addiction Scale (OPAS) using the behavioral addiction model and to explore the relationships between the scale, demographic variables, psychosocial variables, and pornography viewing behaviors. Two studies were conducted, the first of which involved two phases. The findings from Study 1a and Study 1b reveal that the OPAS comprises 23 items organized into four sub-scales: Compulsiveness-Uncontrollability, Psychosocial Effects, Sexual Effects, and Tolerance-Withdrawal. Overall, the scale demonstrates consistency and reliability. The results of Study 2 indicate that the OPAS correlates with gender, access to professional support, levels of hopelessness, communication with partners, degree of religious affiliation, engagement with sexual videos, frequency of pornography consumption, time devoted to pornography viewing, longest duration without pornography, impact of pornography on sexual experiences, and influence of pornography on daily life. Communication with partners of the opposite sex, engagement with sexual videos, impact on daily life, and religious affiliation levels are also significant predictors of the OPAS score. These findings are discussed in relation to relevant literature.