Big science refers to scientific megaprojects that require large financial investments, extensive international cooperation, large teams of specialists, and sophisticated and advanced research equipment and facilities. This approach is contrasted with small science, which focuses on individual research or scientific activity of small groups. Big science, especially after World War II, began its development path and today has become one of the main factors of scientific and technological advances in the world. In this regard, big science projects have played a decisive role in the expansion of knowledge in most scientific fields, from physics to life sciences; among them are the international nuclear fusion project, the human brain mapping project, and particle accelerator facilities. Big science and its complex and expensive facilities, which are often beyond the capacity of a single country, have caused a fundamental transformation in the development of science and technology over time. In addition to the complexity of the research equipment and facilities required, one of the most important features of big science is the breadth of collaboration between researchers and scientists; as a result of these collaborations, epistemic communities have been formed that no longer play a mere research role, but are groups that influence major governmental and international decision-making, and sustainable collaborations within them help to stabilize and strengthen international relations through the soft power of science. In addition, international institutions and politicians can use the organizational models of scientific communities to effectively lead global organizations; so that scientific megaprojects can be considered as models for global governance and leadership and used as approaches and solutions to face global challenges. In recent decades, through joint planning and investments, numerous infrastructures in the field of big science have been established in cooperation with leading countries in science and technology, which have played a pivotal role in major scientific advances and the emergence of emerging technologies. Accordingly, it is essential for Iranian science policymakers to prioritize the establishment of big science facilities within the country, as well as the access of Iranian scientists and researchers to global big science infrastructures, so that the country can compete with the scientific leading countries in the field of science and technology.