Aim and objective: The aim and objective of this study was to evaluate the potential of diode laser (DL) to treat dentinal hypersensitivity. Materials and methods: Twelve specimens were obtained from dentin disks of 2 mm thickness prepared from the cementoenamel junction (CEJ) portion of six extracted human third molar teeth. The specimens were divided into two groups of six specimens each. All specimens received treatment with 1% citric acid to remove the smear layer. Specimens in group I (control) received no further treatment. Group II (DL) specimens received irradiation with 810 nm DL at an output power of 0.8 W for 10 seconds in noncontact mode. The specimens were prepared and observed under a scanning electron microscope. The diameters of tubules were analyzed. Results: The mean tubular diameter of the samples belonging to group I (control) was 3.90 ± 0.63 μm. The mean tubular diameter of the samples belonging to group II (DL) was 2.11 ± 0.35 μm. Diode laser specimens showed a statistically significant reduction in the dentinal tubular diameter when compared to the control group. Conclusion: In this study, DL was shown to effectively reduce the dentinal tubular diameters, thereby highlighting its potential to be used in the treatment of dentinal hypersensitivity. Clinical significance: Diode laser shows promise in vitro, in reducing dentinal tubular diameters. And therefore could be used in the treatment of dentinal hypersensitivity, clinically. However, further in vivo studies need to be conducted to establish the efficacy of DL.