In the present study, microwave-assisted acid pretreatment (MAAP) was employed to reduce the recalcitrance of sugarcane bagasse (SCB). The pretreated SCB was subjected to catalytic copyrolysis with LDPE in a lab-scale pyrolysis reactor using ZSM-5 catalyst. The influence of operating parameters affecting the effectiveness of MAAP (pretreatment time, pretreatment temperature, level of microwave power, and sulfuric acid concentration) on (i) yields of copyrolysis products, (ii) compositions of crude bio-oil, and gasoline range oil (GRO) (a cut obtained by simple distillation of crude bio-oil having boiling point range of 25 to 230 °C) was optimized. Under optimum operating conditions of pretreatment (microwave power, 600 W; sulfuric acid concentration, 1.5 M; pretreatment time, 15 min; pretreatment temperature, 130 °C), the highest crude bio-oil yield of 43.84% and least biochar yield of 17.65% were observed. The crude bio-oil obtained by pretreated SCB (PT SCB) contained 25.63% gasoline range fraction compounds (GRF), which was 1.96 times higher than the corresponding value for untreated SCB (UT SCB). GC HRMS analysis of GRO showed that it contains 33.14% monoaromatic hydrocarbons, 28.87% C5–C12 alkanes, 11.24% C5–C12 olefins, 25.64% oxygenated compounds (including phenols, furans, esters, and other oxygenated compounds), and 1.14% naphthalenes and indanes. The fuel properties of GRO were estimated and found to be reasonably closer to properties of commercial gasoline.