Representative data to support manuscript entitled 'Metastable austenite driven work-hardening behaviour in a TRIP-assisted dual phase steel' by Ennis, Jimenez-Melero, Atzema, Krugla, Azeem, Rowley, Daisenberger, Hanlon and Lee. Following files are included in the zip archive: Folder containing 1D spectra of bulk XRD pattern; Folder containing all figures from the related paper; Folder containing mechanical property data for DP and TADP materials and refined XRD data for Austenite fraction as function of equivalent stress. Excel file containing in-situ and ex-situ XRD data incl. strain partitioning analysis and raw tensile data for DP and TADP steels incl. calculated values for true stress and true strain. Work hardening rate is calculated as first derivative of true-strain-true stress curve. Flow stresses for each phase are inferred from analysis of the 2nd derivative of the curve. Two further data sets including stress-strain data from tensile tests and austenite fraction (measured ex-situ) for two TRIP700 steels with similar composition and heat-treatment cycle as the TADP steel.