In this work, thermogravimetric data were used for to study the thermal degradation of corn starch with and without thermo-alkaline treatment. Flynn–Wall–Ozawa, modified Coats–Redfern, and Kissinger methods were used to determine the activation energy. Corn starch treated with calcium hydroxide exhibited the highest activation energy values during the whole thermal degradation process which could be related to the physical crosslinking process between starch constituents and Ca ions as was confirmed by the infrared analysis. The energy activation was dependent of the conversion, indicating that this degradation is a complex process. DSC at high temperatures, used for starch, corroborated that the degradation in this material is a complex process governed by different chemical reactions. Thermo-alkaline treatment has a decelerator role in thermal degradation of corn starch.