The chemical equilibrium of five positional isomerization reactions of aryladamantanes with different structures was studied in the liquid phase in the presence of AlCl3 in the range 303-423 K. Contributions to the equilibrium constants were analyzed using experimental and calculated data. The contributions were from symmetry, intermolecular interactions, differences in heat capacities of isomers, overall rotation of molecules, free or hindered rotation of groups in molecules, contribution of vibrations, differences in conformational composition, and intramolecular effects of interaction of substituents in molecules involved in the reaction. The significance of these contributions to the equilibrium constants of the transformations in question was shown. The enthalpies and changes in entropy for the reactions in the liquid and gaseous states were determined and discussed. A comparative analysis of the thermodynamic characteristics of positional isomerization of aryladamantanes, methyladamantanes, methyldiamantanes, and phenylcyclohexanes is given.