Gas-assisted injection molding (GAIM) produces parts with hollow internal sections and it provides benefits to powder injection molding (PIM) due to the less material usage and reduced time required for de-binding processes. In this study, the effects of processing parameters on gas penetration length of gas-assisted powder injection molding (GAPIM) were investigated for 316 stainless steel (SUS316L) powder feedstock based on the Taguchi method. The processing variables were melt temperature, shot size, gas pressure, and gas delay time. The most significant parameters affecting gas penetration length were gas delay time and shot size, while the significance of melt temperature and gas pressure was low relatively.