Strategic Environmental Assessment (SEA) is a process used for the evaluation of environmental impacts at a higher level of decision-making than that of each individual project, i.e., during the preparation and implementation of policies, programs, and plans, with the objective of incorporating the aspect of sustainable development in the early stages of planning. However, the “strategic” nature of SEA is the cause of frequent confusion among the responsible competent institutions and professionals regarding the selection of the most appropriate methods and techniques for each individual situation. At the international level, current research indicates a certain ambiguity in the use of methods and techniques in every step of SEA processes. In Greece, despite the implementation of SEA procedures in the preparation of a number of plans and programs after the transposal of the SEA Directive, to date, no attempt has been made to systematize the current experience and practice from the utilization of methods and techniques. The objective of the present study is to analyze and provide a comparative evaluation of the Greek and international experience, on the one hand with the systematic examination of Strategic Environmental Impact Assessments, and on the other with primary research, through questionnaires addressed to Greek practitioners. An important observation is that, both in Greece and abroad, there are inadequacies in the existence and/or the use of guidance manuals for the selection of the most appropriate methods and techniques, and only a limited range of methods and techniques are used in comparison with those catalogued in international literature.