Reaction synthesis is a processing technique where the thermal activation energy needed to form a compound is provided by the exothermic heat of formation of the thermodynamically stable product. This type of synthesis has been used to form a variety of ceramics, intermetallics, and in-situ composites. In this work, the effects of changing the stoichiometry of the titanium aluminide matrix, and the effects of extrinsic reaction variables on the behavior of the reaction were studied and compared to theoretical predictions. It was shown that changing the stoichiometry of the titanium aluminide did have an effect on the measured heat of reaction; however this did not match the prediction. Changing the extrinsic variables of titanium and aluminum particle sizes also showed a significant effect on the behavior of the reaction.