Background: The present study investigates the reliability and validity of the Positive–Negative Relationship Quality (PN-RQ) scale in Turkey. This study aims to test different factorial models including orthogonal factors model, correlated factors model, one-factor model, and bifactor model. Methods: In order to determine the validity and reliability of the scale, two studies were performed. The first was carried out with emerging adults (university students) who were in a romantic relationship (148 females, 43 males, and 2 unknown) and had the main purpose to examine the structure validity of the measurement tool in the Turkish sample with an exploratory analysis. Study 2 was performed online with 513 married adults (359 females, 149 males, and 5 unknown); confirmatory findings and criterion validity studies were added. Results: Exploratory factor analyses revealed that relationship quality had a two-factor structure and that there was also a negative relationship between the factors. Confirmatory factor analyses on the married sample showed that the bi-factor model provided evidence for the multidimensional nature of the scale. Both studies demonstrated high internal consistency. Conclusion: There is evidence for reliability and validity in the Turkish version of the PN-RQ scale to measure both positive and negative aspects of the relationship. The PN-RQ scale will be highly functional for social and clinical psychologists who work on close relationship issues in Turkey.