Associated withexpansive soils, heave, settlement, and lateral distress are the major geotechnical problems known worldwide to light weight structures. In countries like Ethiopia, geology, climate, environment, andtopography factors influenced the development of expansive minerals clay soils having a different nature in different places. Now a day, the prime cause of the damage of structures built in expansive soil areas is cantered towards design and construction of foundation without conducting the necessary and an appropriate expansive soil tests. These is primarily due to the unavailability of the appropriate laboratory testing machine particularly the Swelling Pressure testing equipment. Moreover, the greatest challenge in countries like Ethiopia is the wrong attitude of the young Engineers on the design and construction of structures practiced in Expansive Soil sites. Therefore, to alleviate this problem and support the development in Ethiopia, this study on characterizing the geotechnical engineering properties of the expansive soils are focused to develop the Swelling Pressure Predictive Model from Index Property of Expansive Soils of Dilla Town. Accordingly, in this study, twenty (20) disturbed and undisturbed Expansive Clay soil samples are collected from different sites of Dilla town and all the required laboratory tests (IndexSwelling Pressure and Free Swell test) were conducted. Specific to this research, statistical software (NCSS-12) was employed to investigate the significance of individual independent variables in model development. In the study about 18 multiple regression analyseswith subset selection trials for modelling Swelling Pressure from various soil index properties were performed. Subset selection option of the NCSS-12 statistical software is used for the task of finding a small subset of the available independent significant variables that does a good job of predicting the dependent variable. The normality of the data was checked and an appropriate data transformation when necessary is applied. Therefore, based on theoretical, experimental and computational studies made, the soils of the townup to 2.5m is found covered by thick black clay soil with abundant clay fraction in the range of 72.81 – 75.27% and are potentially expansive characterized by Soft Clay with a High Plasticity nature. The swelling pressure of the expansive soils of Dilla town for different clay content, dry density and water content is very high in the range of 179.25 - 238.75 kPa.