Geopolymer concrete (GPC) is considered the most promising eco-friendly material alternative to Portland Concrete (PC) and an opportunity to utilize by-products in concret manufacturing. One key driver in geopolymer development is the desire to reduce greenhouse gas emissions from the production of Portland cement products. Geopolymers exhibit good mechanical propertieps, durability and thermal resistance. Due to the relatively low tensile strength of GPC fibers may be added to overcome this deficiency.This paper presents an experimental investigation for the parameters affecting the properties of the geopolymer based materials. The investigated parameters affecting of of the geopolymer mortar (GPM) included age of mortar at the time of testing (7 days and 28 days), concentration of morlar ( 8 M, 10M, 12M and 14M) , ratios of activator to binder (0.5,0.55,0.6), ratios of Sodium Silicate to Sodium Hydroxide Solution by mass (1:1, 1.5:1, 2:1 and 2.5:1), Curing time (48 and 96hrs) and rest period (RP) (24 and 48hrs). More over this study is directed to investigate the influence of adding different fiber types (steel and polypropylene) as well as different fiber contents (0, .5, 1, and 1.5 %) to GPC mixes on the mechanical properties. The investigated properties included compressive, splitting tensile and flexural strengths. Based on the test results, it was observed that the fibers reinforced geopolymer concrete (FRGPC) have relatively higher strength than geopolymer concrete (GPC) and was shown that using 1.5% steel fibers showed the most improvement in the mechanical properties. The percentages of enhancements were 23.06%, 85.23% and 55.66% for compressive, splitting and flexural strengths over the (GPC) mix with out fibers, respectively.