This study presents the validity and reliability analyses of the Psychological Flexibility in Romantic Relationships Scale. The measurement tool, developed for individuals who have been in a romantic relationship for at least six months, has a unidimensional structure consisting of 6 items. For the validity and reliability studies, data were collected from two separate study groups in 2024. The first group consisted of 80 participants, while the second group included 218 participants. The data were analyzed using SPSS 29.00 and AMOS 24.00. Exploratory and confirmatory factor analyses were conducted to assess the construct validity of the scale. The results confirmed that the 6-item unidimensional structure of the scale was valid. Reliability and internal consistency analyses indicated that the items were highly discriminative and reliable. Overall, the findings demonstrated that the Psychological Flexibility in Romantic Relationships Scale is a valid and reliable measurement tool.