The effect of Pt particle size on propane combustion was investigated over Pt/ZSM-5 catalysts. The particle size of Pt was controlled by adjusting the SiO2/Al2O3 ratio in H-ZSM-5, a cation in ZSM-5, and an aging temperature. Several techniques such as inductively coupled plasma-atomic emission spectroscopy, N-2 physisorption, CO chemisorption, C3H8 chemisorption, solid-state Al-27 magic-angle spinning nuclear magnetic resonance spectroscopy, transmission electron microscopy, and infrared spectroscopy after CO chemisorption were used to characterize the catalyst. Among Pt catalysts supported on H-ZSM-5 with different SiO2/Al2O3 molar ratios, Pt/H-ZSM-5 (SiO2/Al2O3 = 150) having small Pt particles and large external surface area showed the highest specific reaction rate for propane combustion. The specific reaction rate decreased with an increase in the Pt particle size in Pt/H-ZSM-5 (SiO2/Al2O3 = 23) catalysts with different Pt particle sizes. Although Pt/Na-ZSM-5 catalysts had larger Pt particles than Pt/H-ZSM-5 catalysts, the former showed a lower apparent activation energy for propane combustion than the latter.