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), Δ9-tetrahydrocannabinol (Δ9-THC), and Δ8-tetrahydrocannabinol (Δ8-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, Δ8-THC, and Δ9-THC present in oil samples.