Lemon grass, Cymbopogon citratus Stapf, is an important aromatic plant used by industries that producefragrances and aromas. This topic has been investigated very little in terms of arbuscular mycorrhizalfungi (AMF) associations and the effects of heavy metals, such as lead (Pb), in its metabolism. This studyaimed to evaluate the essential oil (EO) content and the chemical composition obtained from lemongrass cultivated with or without AMF Rhizophagus clarus inoculums under five levels of Pb in the soil. Theexperiment was conducted in a greenhouse for six months and consisted of a completely randomizeddesign. A 5 × 2 factorial was used for five levels of Pb (0, 50, 100, 500, and 1000 mg Pb kg−1soil) andtwo levels of AMF inoculation (with or without R. clarus) and five replicates, totaling 50 experimentalunits. The EO content was determined and the chemical composition analyzed by GC and GC/MS. Thesecondary metabolites were affected by the presence of Pb in the soil as well as by the AMF association,which altered the content and chemical composition of EO. The levels of 500 and 1000 mg Pb kg−1soiltogether with AMF association increased EO content up to 0.69%. In total, 21 components of EO wereidentified, and along the increasing levels of Pb, the plant metabolism changed and altered the majorcomponents of EO. Without AMF inoculation, the major constituent of EO was citral, with concentrationsranging from 36.66 to 45.08% for the lowest levels of Pb. With AMF inoculation, EO was composed mainlyof geranial, with concentrations ranging from 39.27 to 58.97% for all Pb levels. Without AMF inoculation,the concentrations of geranial ranged from 43.66 to 62.95% for the highest levels of Pb. High levels ofcitral and geranial are of great interest to the aroma and fragrance industry, and citral is a basic substancefor the synthesis of vitamin A and ionone.