Introduction: The aim of this study was to investigate the relationship between fibromyalgia disease activity and temporomandibular joint disorder (TMD) level in patients with fibromyalgia, as well as TMD-related symptoms of cervical muscle endurance, cervical pain, anxiety and kinesiophobia. Method: The study comprised 50 participants, consisting of 3 males and 47 females, all diagnosed with TMD and fibromyalgia. The severity of TMD was gauged through the Fonseca Amnestic Questionnaire (FAQ), while the functional status of the subjects was evaluated using the Fibromyalgia Impact Questionnaire (FIQ). Cervical muscle endurance was measured via the Cervical Flexor Muscle Endurance Test (CFMET). Additionally, cervical pain, kinesiophobia, and anxiety levels were assessed utilizing the Visual Analog Scale (VAS), Tampa Scale for Kinesiophobia (TSK), and Beck Anxiety Scale (BAS), respectively.Formun Üstü Results: A statistically significant positive correlation was observed between the level of TMD and the functional status of the patients (p < 0.05). Conversely, no statistically significant correlation was discerned between TMD and the variables of VAS, CFMET, TSK, and BAQ (p > 0.05). Notably, a significant correlation was detected between TMD and the disease activity among fibromyalgia patients exhibiting TMD. However, no statistically significant correlation was identified between head and neck complications, kinesiophobia, and anxiety within the fibromyalgia patient cohort. Conclusion: Although it is recognized that these clinical parameters in the context of fibromyalgia do not depend solely on the level of TMD, it is imperative that they be evaluated collectively when evaluating the patient.