Psychosocial factors influence the development, exacerbation, or aggravation of some oral diseases. However, the possible relationship between personality traits, affective disorders, and psychological stress in oral diseases, and their impact on oral health-related quality of life (OHRQoL), has not been fully clarified. The aim of the present study was to determine the association of neuroticism and stress with the presence of oral lichen planus (OLP), and to discover whether or not these factors impact OHRQoL. This is a case-control study matched for age and sex. The case group (OLP group) was composed of 20 patients diagnosed with OLP, while 20 people with a diagnosis of lesions not associated with stress formed the control group. Three instruments were used: the Holmes–Rahe Social Readjustment Scale, the Five Factor Personality Model, and the OHIP-49. Neuroticism obtained a score of 25.5 (±5.4) in the OLP group, which was higher than the control group value (21.7) (±5.1) (p= 0.03). The OLP group showed a worse quality of life (p< 0.05); the most affected dimensions were psychological discomfort and physical disability. It is important to include a psychological profile to establish a comprehensive treatment for these patients. We propose the recognition of a new area of clinical oral medicine: psycho-stomatology.