This study on the Hot Compressed Water (HCW) gasification of oil palm Empty Fruit Bunch (EFB) fibers was investigated in a batch system using high-pressure autoclave reactor. Reaction parameters subjected for investigation were solid loading and reaction temperature. Solid particle size, amount of water and reaction time were fixed at 250 < X < 500 μm, 300.0 g water and 30 min, respectively. The optimum reaction conditions found were 5.0 g solid loading and 380°C which produced gases mainly of CO2, CO, H2 and CH4 with gasification efficiency of 32.15% and H2 yield of 7.22%. This study also focused on the role of a homogenous catalyst, K2CO3 and its effects towards the reaction. The optimal amounts identified were 3.0 wt.% (K2CO3) with gasification efficiency achieved of 39.04% and H2 yield 19.03%, respectively. This had proven the important role of homogenous catalyst to increase the hydrogen selectivity of gasification process and thus render the process more feasible for synthesis gas production. The results of these findings were critical towards a more sustainable usage of EFB for renewable energy generation.