Benzyl penicillin, known as penicillin G (PG), is a beta-lactam antibiotic and also a weak monocarboxylic acid. The penicillin G extraction from aqueous solution by Amberlite LA-2 in different diluents, that is, octan-1-ol, nonan-1-ol, 3-methyl-1-butanol, ethyl ethanoate, propyl ethanoate, 4-methylpentan-2-one, octan-2-one, octane, and decane has been studied. According to experimental results, some thermodynamic parameters, such as distribution coefficients (K-D), loading factors (Z), and the extraction efficiency or degree (E), were calculated. The best extraction efficiency, distribution coefficient, and loading factor were determined using 3-methyl-1-butanol diluent as values of 92.63, 12.25, and 0.195, respectively. The linear solvation energy relationship (LSER) model was regressed for the experimental results of the distribution coefficient with the regression coefficient (R-2) as 0.96. Besides, the equilibrium model for the extraction degree of alcohols has been applied and compared with experimental data.