Abstract: In Tunisia, oak forests are attacked permanently and in an episodic manner by several defoliating Lepidoptera. This work was conducted between February and April 2018 and aimed to study the infestation of Quercus coccifera by five Lepidoptera species (Orgyia trigotephras, Acrobasis sp., Phyllonorycter messanniella, Acrocercops brongniardella and two Pammene spp. species) competing for the same part of the host plant in two study sites, in the North of Tunisia. The largest (Dmax) and the smallest (Dmin) crown diameters were measured to calculate the mean diameter (Dm). In field, infested leaves were identified according to the specific damage caused by each species then a direct counting of shelters of caterpillars of four Lepidoptera and egg masses (for O. trigotephras) on the host plant was done. The highest percentage of infestation was recorded for the two Pammene species (54%) in Jebel Abderrahmane and for Acrobasis sp. (77%) in Dam Ziatine. Contrariwise, infestation by the two leafminers P. messaniella and A. brongniardella was lower on both sites. Egg masses of O. trigotephras were observed only in Jebel Abderrahmane. This difference of infestation among insects may be due to temperature fluctuations that can have a direct effect on the physiology/behavior of insects, and indirect effect on the quality of the foliage (host plant).