Poly(methyl methacrylate), PMMA, or acrylic microspheres and spheres are spherical polymer beads that are a transparent thermoplastic synthesized from methyl methacrylate polymer. PMMA microbeads are known for high impact and heat resistance, and good tensile and flexural strength. These strong yet lightweight polymer microspheres are often used as spacers, fillers, and reference particles for a variety of specialty applications in life sciences, medical technology, MEMS, optics and development of high performance composites. Uncoated poly(methyl methacrylate) or PMMA microspheres and spheres are often used in manufacturing of porous ceramics, self assembled microfluidic devices, and in biomedical research. Also often used as a lightweight alternative to glass microspheres.

Conductive silver-coated poly(methyl methacrylate) beads are often used in bondline spacer application where conductivity of the silver coating and the ability of the polymer to slightly compress under pressure is desired for a particular application, such as manufacturing of conductive epoxies and adhesives.