Measurements leading to the calculation of the standard thermodynamic properties for gaseous 2-methylquinoline (Chemical Abstracts registry number [91-63-41) and 8-methylquinoline (Chemical Abstracts registry number [611-32-5]) are reported. Experimental methods include oxygen bomb calorimetry, adiabatic heat capacity calorimetry, vibrating-tube densitometry, comparative ebulliometry, inclined-piston gauge manometry, and differential scanning calorimetry (dsc). The critical temperature was measured with a differential scanning calorimeter. The critical pressure and critical density were estimated. Standard molar entropies, standard molar enthalpies, and standard molar Gibbs free energies of formation were derived at selected temperatures between 298.15 K and 700 K. All results are compared with experimental values reported in the literature.