Abstract: A technique of laser peen forming on a microscale has been developed, which does not require a confining (tamping) layer. This paper reports on the results of studies carried out on 75-μm-thick steel samples using pulsed Nd:YAG lasers operating at 1,064-, 532- and 355-nm wavelengths and relatively low beam powers of 5, 2.5 and 1.8 W, respectively. Empirical data are presented to demonstrate the active forming mechanism and to characterise the process. The process was found to produce a bending towards the laser beam at any angle of incidence, including at 0° (or parallel) to the surface. A bend angle of up to approximately 28° was possible when the incident angle is 90°. The process was found to be reversible by reverse side irradiation. The results from these experiments have been compared to samples formed using continuous wave thermal laser forming. The laser peen-formed samples do not show evidence of a heat-affected zone seen in thermal laser forming, which, together with thermocouple analysis, indicates that the active laser peen forming process is non-thermal.