AbstractBark is one of the most under-utilized types of lignocellulosic biomass in the forest industry. In this study, bark fast pyrolysis was optimized for phenols yield using response surface methodology (RSM), considering the pyrolysis temperature, gas flow rate, and biomass particle size. The bio-oil generated under optimal conditions was then characterized by gas chromatography-mass spectrometry (GC-MS), ultimate analysis, and several physical methods. A regression equation was estimated based on the statistical analysis. It was found that the optimal conditions for phenols yield were 485 °C (pyrolysis reaction temperature), 28 L/min (gas flow rate), and 0.35 mm (biomass particle size), giving an experimental phenols yield of 13.2 wt%. The bio-oil obtained in optimum conditions met ASTM standard D7544-12 and contained up to 30.42% phenols. This renewable, phenol-rich bio-oil may be a good feedstock for phenolic-based chemicals, such as phenolic resin and phenoplast.