The Islamic Development Bank (IsDB) is a Saudi Arabia-based multilateral development finance institution headquartered in Jeddah, focused on Islamic finance through interest-free financing in accordance with Sharia principles. Established in 1973 by members of the Organisation of Islamic Cooperation (OIC), it began operations in 1975 to foster economic development and social progress in its 57 member states, with Saudi Arabia holding the largest shareholding at around 23-27%. The IsDB supports infrastructure, agriculture, education, health, poverty alleviation, private sector development, trade financing, and humanitarian aid projects, emphasizing sustainable development goals, risk-sharing, and ethical investment. It operates through various windows, including ordinary capital resources, Islamic Social Financing, and funds for specific purposes, mobilizing resources from member contributions, sukuk issuances, and partnerships with international organizations like the World Bank. Since inception, it has approved over $200 billion in financing and expanded its role to include global partnerships with non-member countries and a focus on Least Developed Member Countries and post-conflict reconstruction. Governed by a Board of Governors comprising finance ministers from member states and a Board of Executive Directors, the IsDB maintains high credit ratings (AA+ from S&P). Notably, it provided funding for the Islamic Society of Boston's mosque construction, highlighting its involvement in community and religious infrastructure worldwide.