Numerical solutions based on the finite element technique is widely used over the last decade to develop a realistic model. FEM techniques are sufficiently capable to capture the underlying physics of complex nonlinear problems such as machining. Micro-turning is one such domain of manufacturing process in which material removes at micron range and extensively used in the fabrication of miniature parts such as electronic components, semiconductors, micro-tools. Ti-6Al-4V is widely used material due to its high specific strength and high corrosion resistance. The present work proposes a three-dimensional finite element study based on coupled thermo-mechanical transient analysis of micro-turning process to predict the surface and sub-surface residual stress of Ti-6Al-4V. The strain gradient factor has been coupled with Johnson-Cook flow model to capture the scale effect. Johnson-Cook damage criteria is used to capture the material separation. At low feed, radial and axial residual stresses altered the nature compressive to tensile at a depth 12 μm due to rubbing and ploughing, led to heat generation. Compressive residual stress increases with feed rate because of high strain rate and moreover, the circumferential residual stress (~ 1000 MPa) is found to be much higher than radial and axial. At low feed 3 μm/rev, maximum axial residual stress found at a depth 4 lm from machined surface due to accumulation of dislocation density owing to size effect. The predicted residual stress is validated with Nanoindentation technique and found to be in good agreement. All material properties of Ti-6Al-4V were measured to calculate the residual stress.