BACKGROUND Temporomandibular joint disorders (TMJD) affect the muscles of the mandible or the temporomandibular joint (TMJ). The objective of this case-control study was to compare mandibular and cervical joint mobility in young adults diagnosed with TMJD to a healthy control group. MATERIAL AND METHODS We enrolled 60 participants aged 18-30 years, split evenly between 30 TMJD patients and 30 healthy controls. We employed a millimeter gauge to measure TMJ mobility and a tape-based tool for assessing the range of cervical mobility. RESULTS Our data revealed that TMJD patients exhibited a significantly reduced range of mobility in both the TMJ and cervical spine compared to controls. Controls demonstrated a greater mean cervical mobility through left and right lateral flexion movements (P<0.01 and P<0.05 respectively), as well as right and left rotations (P<0.05). Additionally, they showed significantly higher mandibular mobility across all tested parameters (P<0.001). Within the TMJD group, we observed a significant correlation between cervical and mandibular mobility (P<0.05). CONCLUSIONS Our findings underline that TMJD patients possess significantly diminished mandibular and cervical mobility, particularly in lateral movements and rotations, compared to those without the disorder. The observed correlation between cervical and mandibular mobility in the TMJD group implies the necessity to consider these interconnected aspects when designing rehabilitation programs, thereby enhancing patient quality of life and impeding further mobility deterioration.