Lignocellulosic biomass, a renewable and biodegradable resource from forestry and agricultural by-products, is composed of lignin, cellulose, and hemicelluloses. This chapter explores the transformative potential of lignocellulosic biomass as a sustainable feedstock for paper and packaging applications, addressing the growing demand for environmentally friendly alternatives to fossil fuel-derived and plastic-based materials. The pretreatment and processing of agricultural waste, forestry residues, and industrial biomass streams into cellulosic pulp offer opportunities for the production of high-value paper products and precursors to smart packaging applications. The chapter also explores the valorization of lignocellulosic biomass, including various pretreatment and processing methods, such as physical, chemical, and biological (enzymatic) approaches necessary to overcome biomass recalcitrance, particularly due to lignin and other minor constituents. The key challenges in utilizing lignocellulosic biomass as feedstock for paper and packaging applications include lignin content, water absorption, and generation of inhibitory compounds during pretreatment. The different processes involved in the production of cellulosic pulp for paper and packaging, including delignification and subsequent transformation into value-added products such as biofuels and chemicals, are also discussed.