This chapter discusses methods for assessing product sustainability, emphasizing the lack of a universal definition or framework. It addresses the challenge of evaluating ecological, economic, and social dimensions, as industries prioritize different goals and apply diverse methods. Both one-dimensional footprint approaches and holistic, multidimensional models are introduced. One-dimensional methods such as the Product Carbon Footprint, Ecological Footprint, and Water Footprint capture a single impact category like greenhouse gas emissions, land use, or water consumption. Examples include methane emissions from cattle farming, land-use data in agriculture, and water balances in production, with standards like ISO 14067 ensuring comparability. Broader decision-making tools integrate multiple criteria: utility analyses, technical-economic assessments, and pairwise comparisons structure alternatives by weighting ecological, economic, and social factors. Methods such as the Analytic Hierarchy Process and Multi-Criteria Decision Analysis enable transparent evaluation, illustrated by LED lighting outperforming alternatives in efficiency and lifespan. Comprehensive models like Material Input per Service Unit (MIPS) and Life Cycle Sustainability Assessment (LCSA) combine environmental (LCA), economic (LCC), and social (SLCA) analyses. Databases including Ecoinvent, GaBi, and openLCA provide data infrastructure. Finally, eco-efficiency links economic value creation to ecological impact, offering strategic orientation for organizations to balance profitability with environmental responsibility in sustainable product development.