We describe the results from the isolation and structural identification of the acylglycerol constituents of fruits from wild plants belonging to different species of Thapsia (Apiaceae). The isolated lipid fractions were analyzed and characterized by chemical, chromatographic, and spectroscopic means. In particular, 13C nuclear magnetic resonance data allowed the identification of petroselinic acid as the major fatty acid esterified to glycerol in the fruit oils from all the plant samples. This was also confirmed by gas chromatography (GC) and GC-mass spectrometry analyses of fatty acid methyl and butyl esters derivatives from Thapsia oil. The genus Thapsia should be regarded as a useful source for the extraction of petroselinic acid, which represents an important oleochemical raw material.