The research presents a study on the Effectiveness of Employing Digital Flat Design to achieve Sustainability. By addressing the concept of Sustainable Development with its various definitions and pillars, with examples of schools and artistic movements that adopted the idea of Sustainable Development before its concept was formally adopted by the United Nations World Commission on Environment and Development in 1987; Through which to move to Sustainable Digital Design and methods of evaluating the extent of achieving functional Sustainability through several questions formulated in the form of a set of principles with a focus on clarifying the role of Flat Design in making the Digital Design more Sustainable. At the end of the research, a set of examples of digital designs seeking sustainability globally and locally were presented with analysis to clarify the percentage of achieving their goal aesthetically by addressing the appropriateness of the design and the symbols used for the product kind or service provided; And functionally, as the researcher conducting a questionnaire on a random research sample to clarify the percentage of those sites achieving their job objective; And environmentally, by studying the percentage of the site's achievement of sustainability relative to other sites that were previously tested, in addition to the amount of carbon dioxide emitted by the devices and the amount of electrical energy consumed during its use.