An amine-terminated cyclophosphazene and 3-aminopropyltrimethoxysilane-functionalized rice husk ash incorporated halogen-free flame-retardant epoxy composites (ATCP/FRHA/Ep) were developed and their thermal, dielectric, hydrophobic and flame-retardant properties were analysed. The cone calorimeter and contact angle results confirm that the ATCP and FRHA materials impart good flame-retardant and water resistance properties to the resultant epoxy composites. A significant improvement in the flame-retardant, glass transition temperature, char yield and dielectric properties was noticed, due to the synergetic effects imparted from the unique combination of phosphorous and nitrogen in the phosphazene ring as well as silica present in the rice husk ash. Obviously, this ATCP/FRHA/Ep flame-retardant system paves a new possibility for high performance non-halogen flame-retardant polymeric materials. Hence, they have become potential candidates for fire-resistant applications in electronic and microelectronics as a sustainable non-flammable polymeric material.