Abstract: In Cabra, Spain, we selected an olive grove with a dense presence of moss as a cover crop (85% surface area) in order to study the influence of its presence on the growth of weeds, as well as its tolerance to common herbicides and chemical substances used in olive crops. We evaluated the installation of 6 different weed species (Brachypodium distachyon, Capsella bursa-pastoris, Papaver rhoeas, Sagina apetala, Sinapis alba and Stellaria media) in pots kept in a semi-protected environment for non-vegetation soil facing to soil covered with moss. The emergence that was measured over 10 weeks showed significant differences between species, which were established themselves quicker and in greater abundance in the absence of moss. The evaluation was held based on the analysis of variance and Tukey test at P < 0.05. Over a period of six weeks we also evaluated the tolerance/susceptibility to 19 different herbicides authorized in olive groves in Spain and Israel and to chemical substances such as fertilizer of ammonium sulfate and fungicide containing copper oxychlorid. Significant differences were found in the moss’s reaction to the distinct treatments in both the time of reaction and recovery. On the one hand the moss was very susceptible to fertilizer but on the other hand tolerated fungicide. The first experiment was based on a factorial design (species x soil/moss) with 4 repetitions and 100 seeds per pot (48 samples) and a randomized design with 5 repetitions (125 samples) in the second experiment. The presence of moss in the soil of the olive grove, and its reduction or delay in the installation of weeds, demonstrates a non-chemical control method which could be useful in the integrated management of weeds. Its tolerance to several herbicides that are commonly used in olive groves, encourage its presence and its advantage as a good cover crop which might reduce over time the need for the application of herbicides.