One of the critical needs of a Three Way Catalyst (TWC) model is to be able to predict light-off. This is crucial for application studies and vehicle architectural studies because most of the emissions from a TWC occur before light-off (called cold-start emissions). Laboratory experiments give detailed insights to the reaction mechanism and analytical forms of the rate expressions as they are well-controlled and well-behaved as compared to vehicle tests. However, to predict emissions on a vehicle test, the laboratory-estimated kinetic parameters are not entirely capable because of the various uncertainties in the vehicle tests. In this work, six different vehicle data sets are used to calibrate and validate the TWC global kinetic model. Our emphasis in this work is restricted to predicting the light-off (cold-start emissions) in TWC. The kinetic model is calibrated using 4 vehicle data sets (which use the FTP drive cycle) using iSIGHT software package. The kinetic parameters of the various reactions occurring in the TWC are estimated to match the experimental data through exploratory and local optimization methods. A systematic approach (with increasing complexity) is used to estimate the kinetic parameters. The estimated parameters are then used to validate the model on two different vehicle data sets (one NEDC drive cycle and one FTP drive cycle) with different catalyst compositions and engine power (and hence different engine out exhaust compositions). The model with estimated kinetic parameters predicts the light-off reasonably well for the new data sets. The parameter estimation approach in this work is kept as generic as possible to exhaust aftertreatment devices, and a set of guidelines for parameter estimation (specifically for use in exhaust aftertreatment devices) is presented (in the Appendix).