The decompositions of tertiary stibines (R3Sb, R = methyl, vinyl, isopropyl) were studied in an atmospheric pressure flow tube reactor, using D2 and He as carrier gases. D2 was used to isotopically label the byproducts in order to elucidate the pyrolysis mechanism. The exhaust products were analyzed by a time-of-flight mass spectrometer. The decomposition of these tertiary stibines in the presence of group Ill precursors was studied in order to simulate the conditions of organometallic vapor phase epitaxial growth. A comparison between the pyrolysis temperatures, decomposition mechanisms, and surface area effects of these Sb source compounds is presented.