Characterization and swelling analysis were performed on Agbaja iron ore to determine its suitability for engineering applications. Microstructure and morphological examinations of the ore were conducted on an inverted metallurgical microscope and SEM/ XDS techniques. Thermogravimetry, Differential Thermal Analyzer, X-Ray Fluorescence, and X-Ray Diffraction were used to analyze the chemical and structural compositions of the ore. The iron ore was heated in the muffle furnace to calculate the swelling percentage. The samples were subjected to temperatures 800oC to 1000oC with an interval of 40oC and a hold time of 30mins to 130 mins with an interval of 20mins. The samples were weighed with a digital weighing balance before and after heating to keep track of their initial weight, final weight and hence, percentage swelling induced by the thermal process. After a 30 mins hold time, 3.12% swelling was obtained at 800oC as the lowest point, while 3.67% was obtained at 1000oC. However, after a hold time of 130mins, 3.93% swelling was obtained at 800oC as the lowest point, while the highest percent swelling of 5.52% were obtained at 1000oC.