This chapter covers research on nonwoody lignin in construction applications with a focus on technical properties, environmental impact, and economics aspects to address the need for sustainable bio-based alternatives in construction materials. The chapter aimed to evaluate reinforcement capabilities, benchmark environmental impacts, assess economic feasibility, compare rheological and mechanical properties, and analyze the influence of lignin source, form, and dosage. A systematic analysis of interdisciplinary studies employing experimental evaluations, life cycle assessments, and economic analyses was included. Findings from previous studies indicate that nonwoody lignin enhances mechanical strength, rutting resistance, and moisture durability in cement and bitumen composites at optimal dosages, though fatigue life and low-temperature performance may decline at higher contents. Life cycle assessments demonstrate significant reductions in carbon footprint and global warming potential compared to fossil-based additives, despite some environmental trade-offs linked to lignin processing. Economic evaluations reveal cost savings through binder replacement and competitive market potential, tempered by scalability and supply chain challenges. Variability in lignin origin, physical form, and chemical modification critically affects material compatibility and performance, necessitating dosage optimization. These findings collectively underscore nonwoody lignin’s multifunctional potential and highlight gaps in long-term field validation and standardized methodologies. The chapter informs sustainable construction practices and guides future research toward optimizing lignin-based material applications.