The essential oils (EOs) of Cymbopogon schoenanthus (L.) collected from six regions of the vast Algerian Sahara were analyzed for their chemical compositions by GC and GC-MS and tested for their antioxidant, antimicrobial and insecticidal activities. The EOs compounds-based cluster analysis permitted to distinguish three groups of similar chemical composition. Among the EOs, those of the group 3 were the most different, while those of group 1 and 2 were much more comparable. Overall, all the strains were sensitive to tested oils except E. coli which was generally the less sensitive bacteria. All the EOs showed weak antioxidant activity in the DPPH test while only those of the group 3 displayed low ferric reductive potential. Contrariwise, the piperitone-rich EOs (group 3) showed the highest effectiveness against the cowpea weevil (Callosobrochus maculatus) with the potent reduction of the femaleâs fecundity and the hatchability of laid eggs, especially EO from Tamanrasset province.