The influence of 3-aminopropyltriethoxysilane, 3-glycidyloxypropyltrimethoxysilane, and neoalkoxytri(dioctyl pyrophosphato)zirconate on thermal expansion behavior, dielectric strength, and are resistance of mica/epoxy composites has been investigated. The addition of mica up to 30% resulted in the reduction of thermal expansion with respect to neat resin. However, the coefficient of linear thermal expansion of 30% mica treated with aminosilane was the least among the various coupling agent-coated filler/epoxy composites. Mica (30%)/ epoxy composites showed the highest dielectric strength values (26 kV/mm), but the highest are resistance was obtained in zirconate-treated mica (30%)/epoxy composite.