The objective of this work is the inventory of lichens in the Hafir forest, it is part of a more general project aimed at studying the lichen flora of the Tlemcen region. The Hafir forest is one of the last Algerian mountainous cork oak forests belonging to the Bético Rifain complex. Our study area enjoys a Mediterranean climate, subhumid with cool winters. Based mainly on random sampling, giving particular importance to the different types of substrate, we were able to sample 73 species of lichens belonging to 16 families and 38 genera. Among these, the Parmeliaceae family is the most dominant with 19 species followed by the Lecanoraceae family which is represented by 14 species and the Physciaceae by 13 species. The physiognomic spectrum shows the presence of 06 lichen categories: foliaceous lichens, crustaceans, fruticose, gelatinous, scaly and leprous. While the classification by type of substrate shows the dominance of corticolous lichens with 48 species followed by saxicolous with 13 species, terricolous with 06 in number and lignicoles and muscicoles with 03 species each. We were able to identify 18 species protected by Algerian law among inventoried lichens. The Hafir forest is home to a very interesting lichen diversity that deserves to be protected, which requires immediate intervention to reduce the anthropogenic pressure exerted and which can pollute this natural environment. Keywords:Lichen - Biodiversity-Sampling- Inventory- Tlemcen