Background: Dentinal hypersensitivity is a common disorder in dental practice, with existing treatments often offering only transient relief. Low-level laser therapy (LLLT) has emerged as a promising option owing to its prolonged pain-suppressing effects and growing patient acceptance. Objective: This study aimed to assess the immediate and sustained efficacy of LLLT, fluoride varnish, and desensitizing paste in treating dentinal hypersensitivity. Materials and Methods: A total of 120 participants were randomly assigned to three treatment groups: Group I (LLLT), Group II (fluoride varnish), and Group III (arginine calcium carbonate paste). Evaluation using the Visual Analogue Scale (VAS) and numerical rating scale (NRS) occurred immediately after the first application, at 1 week, after the second application, and at 15 days, 1 month, and 3 months. Clinical parameters, including plaque index (PI) and clinical attachment level (CAL), were assessed at baseline, 1 month, and 3 months. Results: Intergroup comparisons revealed a statistically significant difference at later time points (15 days, 1 month, and 3 months), with LLLT demonstrating superior efficacy in reducing dentinal hypersensitivity compared to the other two interventions. Intragroup comparisons for clinical parameters PI and CAL exhibited statistically significant differences. However, intergroup comparisons for both clinical parameters did not indicate any statistically significant differences. Conclusion: This study's findings suggest that LLLT offers greater and sustained reduction in dentinal hypersensitivity over a 3-month period, outperforming sodium fluoride varnish and arginine calcium carbonate paste.