Increasing global population and consumption are causing declining natural and social systems. Sustainable development addresses these issues by integrating strategies for economic successes, environmental quality, and social equity. A Sustainability Target Method (STM) provides a practical sustainability target for individual businesses and products through determining the relative indicator resource productivity for environmental performance and the absolute indicator Eco-Efficiency for sustainability. Based on the indicators in STM, this paper investigates the sustainability relationship between a product and its components, between a manufacturer and its suppliers, and proposes a decision making approach to improve product sustainability through component selection and supplier selection. The approaches are illustrated through examples of a generalized product consisting of multiple components, which relates easily to circuit board assemblies and other type of electronic products.