Objective: Oral lichen planus (OLP) is a chronic inflammatory disease of unknown aetiology. The aim of this study was to investigate matrix metalloproteinase (MMP)-1, MMP-9, and MMP inhibitor-1 (TIMP-1) levels in gingival crevicular fluid (GCF) by enzyme-linked immunosorbent assay and to investigate MMP-1, MMP-9, and TIMP-1 levels in gingival tissue by immunohistochemical staining of samples from patients with and without OLP. Design: Twenty-seven patients with OLP (gingivitis, OLPG; chronic periodontitis, OLPP) and thirty healthy non-OLP patients (gingivitis, HG; chronic periodontitis, HP) were included in this study. The MMP-1, MMP-9, and TIMP-1 levels in GCF were determined by enzyme-linked immunosorbent assay. The MMP-1, MMP-9, and TIMP-1 levels in gingival tissue were determined by immunohistochemical staining. Results: The mean levels of MMP-1 and MMP-9 in the GCF of OLPP patients were significantly higher and TIMP-1 was significantly lower than in HP patients; similarly, the mean levels of MMP-1 and MMP-9 were higher and TIMP-1 was significantly lower in OLPG patients than in HG patients. Our findings illustrate that tissue MMP-9 levels were statistically higher and TIMP-1 level were significantly lower in the OLPP group in comparison to the HP group, and the OLPG group in comparison to the HG group. The tissue MMP-1 level in the non-OLP group was found to be lower when compared with the OLP groups. But not statistically significant. Conclusions: Increased levels of MMP-1 and MMP-9 with decreased levels of TIMP-1 in GCF and increased MMP-1, MMP-9 levels and decreased TIMP-1 levels in the gingival tissue of OLP patients in combination with poor oral hygiene may cause increased tissue breakdown. The results of our study provide information about the effects of the periodontal status on the enzyme profiles in GCF and gingival tissue of OLP and non-OLP patients. © 2013 Elsevier Ltd.