Objective: This article evaluates the reliability and validity of the Grandiose and Vulnerable Narcissism Fluctuation Scale (GVNFS) and its short form (GVNFS-SF), which are Turkish adaptations of the FLUX and g-FLUX scales. These scales measure the oscillation between vulnerable and grandiose dimensions of narcissism. Methods: Two studies were conducted with participants aged 18 to 65. Study 1 involved 307 participants, and Study 2 involved 378 participants. Convergent validity was assessed using various psychological scales. Internal consistency was measured, and confirmatory factor analysis (CFA) was used to evaluate the fit indices. Results: Study 1 found that the GVNFS had satisfactory internal consistency, but CFA revealed inadequate fit indices. Study 2 demonstrated that the GVNFS-SF had strong validity and reliability, indicating that the short form is suitable for measuring the fluctuation between grandiose and vulnerable narcissism. Conclusion: The GVNFS-SF is a valid and reliable tool for assessing the oscillation between grandiose and vulnerable narcissism in the Turkish context. However, the full GVNFS may need further refinement to enhance its psychometric properties.