Abstract: Objective To investigate the relationship between 25-hydroxyvitamin D325(OH) D₃ and comorbid anxiety and depression in patients with oral lichen planus (OLP). Methods A total of 127 patients with OLP who were admitted to the First People's Hospital of Xuzhou from January 2022 to December 2023 were selected and set as an OLP group. Another 122 healthy subjects for physical examination during the same period were chosen and set as a control group. Their baseline data were collected. Furthermore, the Hamilton Anxiety Rating Scale (HAMA) and Hamilton Depression Rating Scale (HAMD) scores were evaluated to compare the anxiety and depression of patients in the two groups, and their relationship with serum 25(OH) D₃ levels was analyzed by Spearman correlation analysis. The logistic regression analysis was used to evaluate the factors associated with the anxiety and depression in OLP patients. Results The OLP patients showed lower serum 25(OH) D₃ levels but higher HAMA and HAMD scores than healthy controls, with statistical differences (P<0.05). Among the OLP patients, 77 patients (60.63%) simultaneously presented both anxiety and depression (the comorbid anxiety-depression group), and 50 (39.37%) did not simultaneously present both anxiety and depression (the non-comorbid anxiety-depression group). Differences in disease duration, total reticulation, erythema and ulceration (REU) scores, and visual analog scale (VAS) scores between the two groups of OLP patients were statistically significant (P<0.05). Spearman correlation analysis indicated that serum 25(OH) D₃ levels were negatively associated with HAMA scores (r=-0.421,P<0.001) and HAMD scores (r=-0.473,P<0.001). According to multivariate logistic regression analysis, total REU scores, VAS scores, and serum 25(OH) D₃ levels in OLP patients were associated with the occurrence of comorbid anxiety and depression. Conclusions Low serum 25(OH) D₃ levels in OLP patients are associated with comorbid anxiety and depressive symptoms. It is necessary for clinicians to pay attention to the psychological status of OLP patients, especially the presence of anxiety and depression symptoms in patients with low serum 25(OH) D₃ levels.