This entry discusses the concept of “rizq” in the context of Islamic economics, exploring its etymological, theological, and socioeconomic dimensions. The concept is defined in classical dictionaries as “everything that is utilized,” including material (food, shelter) and spiritual (faith, knowledge) elements. The concept, which appears 127 times in the Qur’ān, offers a balanced perspective by associating it with both divine providence and individual effort (kasb). The Sunnah advocates for legitimate economic activities and underscores the significance of halal earnings. In Islamic economics, sustenance is regarded not only as a means of livelihood but also as the foundation of social welfare. Halal activities, such as trade, agriculture, and production, underscore the productive role of the individual, while unlawful activities, including interest, cheating, and exploitation, are rejected. Concurrently, sustenance fosters social justice through institutional mechanisms such as infaq, zakat, and waqf. The theoretical framework of sustenance is enriched by scholars’ classifications of sustenance, including al-Ghazālī’s “sustenance al-mazmūn” and Ibn Khaldūn’s “utilization-oriented” approach. Islamic economics constructs sustenance as a moral system that integrates work, trust, and social responsibility, with the aim of achieving individual and social welfare. In this system, halāl income is regarded as a divine endowment (fadlullāh), while mechanisms for sharing ensure the sustainability of economic balance.