The article reviews various pretreatment technologies for lignocellulosic biomass to enhance its accessibility for enzymatic hydrolysis and fermentation. The main goal of pretreatment is to overcome the recalcitrance of plant cell walls, which is due to the crystalline structure of cellulose embedded in a matrix of polymers (lignin and hemicellulose). Effective pretreatment can improve sugar yields to over 90% of the theoretical yield for biomass such as wood, grasses, and corn. The review covers physical, chemical, physicochemical, and biological pretreatment methods, highlighting their advantages and disadvantages. Physical pretreatment involves size reduction and crystallinity disruption, while biological pretreatment uses microorganisms to degrade lignin and hemicellulose. Chemical pretreatments include alkaline, wet oxidation, acid, and green solvent methods, each with specific conditions and effects on biomass components. Physicochemical pretreatments like steam-explosion, liquid hot water (LHW), and ammonia fiber explosion (AFEX) combine chemical and physical techniques to disrupt the lignocellulosic matrix. The article also discusses the integration of pretreatment with simultaneous saccharification and fermentation (SSF) to maximize productivity and economic efficiency.The article reviews various pretreatment technologies for lignocellulosic biomass to enhance its accessibility for enzymatic hydrolysis and fermentation. The main goal of pretreatment is to overcome the recalcitrance of plant cell walls, which is due to the crystalline structure of cellulose embedded in a matrix of polymers (lignin and hemicellulose). Effective pretreatment can improve sugar yields to over 90% of the theoretical yield for biomass such as wood, grasses, and corn. The review covers physical, chemical, physicochemical, and biological pretreatment methods, highlighting their advantages and disadvantages. Physical pretreatment involves size reduction and crystallinity disruption, while biological pretreatment uses microorganisms to degrade lignin and hemicellulose. Chemical pretreatments include alkaline, wet oxidation, acid, and green solvent methods, each with specific conditions and effects on biomass components. Physicochemical pretreatments like steam-explosion, liquid hot water (LHW), and ammonia fiber explosion (AFEX) combine chemical and physical techniques to disrupt the lignocellulosic matrix. The article also discusses the integration of pretreatment with simultaneous saccharification and fermentation (SSF) to maximize productivity and economic efficiency.