Purpose: This study investigated the effects of pencil-electrode transcutaneous electrical nerve stimulation (TENS) applied to the masseter muscle on tinnitus severity, bruxism-related discomfort, and quality of life in individuals with chronic bruxism-associated tinnitus and normal hearing. Methods: Thirty-one adults with normal hearing thresholds (≤ 20 dB HL at 0.5–4 kHz) and chronic subjective tinnitus related to bruxism were randomly assigned to a TENS group (n = 18; mean age: 41.4 ± 11.8 years) or a control group (n = 13; mean age: 36.9 ± 8.8 years). TENS was administered four times per week for 5 weeks. Outcome measures included the Tinnitus Handicap Inventory (THI), Visual Analog Scale (VAS; 0–10, assessing bruxism-related jaw discomfort and tinnitus severity), Generalized Anxiety Disorder-7 (GAD-7), Oral Behavior Checklist (OBC), mandibular range of motion (ROM), and SF-36 Quality of Life Scale. All questionnaires were administered at baseline and after completion of treatment. Results: The TENS group demonstrated significant reductions in THI total and subscale scores, VAS bruxism-related discomfort and tinnitus severity, anxiety (GAD-7), and oral parafunctional behaviors (OBC), along with significant improvements in mandibular ROM and SF-36 pain and general health subscales (p < 0.05). No significant changes were observed in the control group. Conclusion: Pencil-electrode TENS applied to the masseter muscle appears to be an effective, non-invasive treatment for bruxism-associated tinnitus, potentially acting through somatosensory neuromodulation mechanisms.