Pyrolysis experiments have been conducted on oil shale, lignite, and biomass, in a 100 mL stainless-steel cylindrical reactor at 725, 825, 925, and 1025 K isothermally. The pyrolysis product distribution is strongly dependent on reactor geometry, temperature, heating rate, residence time, mass transfer velocity, and pressure. Temperature and water-to-sample ratio were pyrolysis parameters. The yield of tarry materials of Goynuk oil shale and Yotagan lignite increased from 23.1 to 29.8% and 13.7 to 21.8%, respectively, while the final pyrolysis temperature was increased from 725 to 1025 K. The yield of gaseous products of Goynuk oil shale, Yotagan lignite, and solid waste increased from 8.6 to 14.9%, 6.7 to 16.1%, and 23.5 to 37.0%, respectively, while the final pyrolysis temperature was increased from 725 to 1025 K. The yield of tarry materials of Goynuk oil shale and Yatagan lignite increased from 21.45 to 37.5% and 11.7 to 25.8%, respectively, while the final pyrolysis water-to-sample ratio was increased from 1:1 to 5:1 at 825 K.