Sorption of nutrients and potential contaminants onto soils has a strong impact on their overall availability, toxicity, and transport. Assessment of sorption energy via titration calorimetry offers a more direct and accurate method for determining thermodynamic parameters of mineral-solution interactions compared to traditional sorption isotherms. In addition, quantification of changes in sorption energy with additional surface coverage can provide some insight into sorption mechanisms and desorption potential. This study utilized titration calorimetry in examination of phosphorus sorption onto a Georgia kaolinite. A supplementary sorption and desorption isotherm was also conducted at the same soil:solution ratio as the titration experiment. Results clearly showed that the titration calorimeter was able to detect the heat of P sorption onto kaolinite. Thermodynamic parameters such as dH and dG were estimated using the heat curve produced, which indicated that there were at least two different sorption mechanisms responsible for removing P from solution. Changes in sorption energy were also indicative of the potential for kaolinite to desorb P into solution.