The document presents a study on developing a simple constitutive model to describe the stress-strain behavior of tropical residual soils. Laboratory tests were conducted on five tropical residual soil samples from Southern India to analyze their stress-strain and pore pressure responses under undrained triaxial loading. The test results showed that the soils exhibited strain softening behavior associated with continued positive pore water pressures. Based on the test data analysis, the researchers proposed a hyperbolic constitutive model relating stress ratio and mean effective stress to strain that captures the stress dependency, nonlinearity and strain softening observed in the tropical residual soils. The model parameters can be determined from standard triaxial tests, making the model simple and practical for engineering applications involving these soils.