Laser microwelding process produces large temperature gradients during the complicated phase transformations of workpiece materials, which results in a high stress level and undesired thermomechanical deformations. Characterization of these deformations becomes important as they might significantly affect performance, functionality, and reliability of the microwelded components. We have developed an optoelectronic holography (OEH) methodology for nondestructive evaluation of thermomechanical deformations caused by laser microwelding processes. OEH methodology provides a unique experimental approach for quantitative measurements of displacements and deformations with sub-micrometer accuracy in full field of view. In this paper, the OEH methodology is described including illumination of a workpiece, formation and acquisition of images, and processing of these images to determine parameters characterizing laser microwelds. Representative results of the OEH measurements of the deformations caused by laser microwelding of metal sheets are presented as a function of different laser welding parameters. In addition, analytical and computational models are also developed to simulate temperature, thermal stress, and thermal deformation fields in laser microwelding process. The investigations indicate that the OEH methodology is a viable tool for characterization of thermomechanical deformations caused by laser microwelding processes, and can help optimizing laser microwelding processes for high precision material-joining applications.