The processing of hollow glass microsphere (HGM) based composites is one of the growing areas in materials research due to the potential of significantly changing material properties even at low HGM concentrations. HGM-epoxy composites are prepared by sonication method. Four weight ratio configurations are considered (1, 3, 5 wt% HGM and 5 wt% NH2 functionalized HGM) and compared with neat epoxy to study the micro-enrichment effect. The influence of low volume HGM and functionalized HGM reinforcement on epoxy in the compressive and thermo-mechanical behavior of the composites were characterized by thermo-gravimetric analysis, dynamic mechanical analysis, and compression testing. The compressive strength of HP5% sample decreased in 101%, as compared with that of EP sample, whereas, storage modulus of HP5% and f-HP5% sample is increased by 27.7 and 32.5%, as compared with the EP sample, but did not significantly affected the thermal stability of the obtained composites. Scanning electron microscope images of the fractured samples had shown a good dispersion and interaction of the HGM in the matrix. By introducing HGM content, there was a remarkable difference in the surface morphology of the fractured surface of epoxy. POLYM. COMPOS., 40:3493–3499, 2019. © 2019 Society of Plastics Engineers. © 2019 Society of Plastics Engineers