In this laboratory teaching experiment, commercial cannabis oils were analyzed by undergraduate organic chemistry students using gas chromatography-mass spectrometry (GC-MS) to investigate three isomeric cannabinoids commonly found in cannabis products: cannabidiol (CBD), [delta][superscript 9]-tetrahydrocannabinol ([delta][superscript 9]-THC), and [delta][superscript 8]-tetrahydrocannabinol ([delta][superscript 8]-THC). The goal was to introduce GC-MS analysis through the relevant topic of product quality inspection, frequently used in various industries such as pharmaceuticals, cosmetics, etc. and which largely involves analyzing the chemical components of a sample. First, to better understand the cannabinoid analytes, students were taught the differences between these structural isomers, including bond locations, stereochemistry, and functional groups--factors which pertain to their pharmacology and drug classification. Finally, students were guided through the basics of GC-MS instrumentation and the process of analyzing GC-MS spectra through the characterization of CBD, [delta][superscript 8]-THC, and [delta][superscript 9]-THC present in oil samples.