Weeding is a practice of primary importance both in conventional agriculture where the intensive use of herbicides can represent a significant environmental risk and in organic farming where this practice is prohibited. Therefore, the need to identify alternative means of controlling weeds is evident. In this respect, allelopathy proves to be a useful tool to be integrated with conventional agronomic techniques for the management of infesting flora. In this work, we investigated the phytotoxic potential of Achillea moschata Wulfen (Asteraceae) against Echinochloa oryzoides (Ard.) Fritsch and Lolium multiflorum Lam., two noxious plants for crops such as rice and wheat. Preliminary anti-germination assays were carried out in controlled conditions by testing both the powder (0.25 g) and the aqueous extract (1%, 10% and 20%) from the A. moschata aerial parts. The obtained results showed that the powder was more effective than the extract in inhibiting seed germination (up to -81.6% vs -48.8% at 20% concentration) and seedling development (up to -99.4% vs -75.9% at 20% concentration) of both target species, although L. multiflorum was more susceptible than E. oryzoides to treatments. Furthermore, the chemical composition of the two used matrices was characterized by Solid-Phase Microextraction (SPME) sampling technique and Gas Chromatograph/Mass spectrometer (GC/MS) analyses. Camphor (25.8% and 49.9%) and 1,8 cineole (25.9% and 20.7%) were the main constituents in the samples, followed by bornyl acetate (6.7%) in the powder and fragranol (10.5%) in the aqueous extract.