An experimental investigation on blended geopolymer specimen using GGBS (ground granulated blast-furnace slag) and RHA (rice husk ash) with coconut fiber (CF) was conducted. GGBS and RHA were blended in the proportion 90:10, while the coconut fiber (CF) content ranged from 0.1 to 0.5% by weight. The specimens were tested for bulk density, apparent porosity, water absorption, compressive strength, split tensile strength, and ultrasonic pulse velocity. Addition of coconut fiber content up to 0.2% shows good results both in compressive strength and split tensile strength at the age of 28 days. Microstructural and mineralogical analysis was studied using scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDAX) on the blended geopolymer specimens. The EDAX analysis identified sodium, aluminum, silica, and calcium as major elements which confirmed the presence of NASH (sodium alumino-silicate hydrate) and CSH (calcium silicate hydrate) in the blended geopolymer. Blended geopolymer composite with addition of coconut fiber is a promising binder as a sustainable material.