Tzedakah or Ṣedaqah (Hebrew: צדקה [ts(e)daˈka]) is a Hebrew word meaning "righteousness", but commonly used to signify charity. This concept of "charity" differs from the modern Western understanding of "charity". The latter is typically understood as a spontaneous act of goodwill and a marker of generosity; tzedakah is an ethical obligation.

Tzedakah (Tzedaka) refers to the religious obligation to do what is right and just, which Judaism emphasizes as an important part of living a spiritual life. Unlike voluntary philanthropy, tzedakah is seen as a religious obligation that must be performed regardless of one's financial standing, and so is mandatory even for those of limited financial means. Tzedakah is considered to be one of the three main acts that can positively influence an unfavorable heavenly decree.

The word tzedakah is based on the Hebrew (צדק‎, Tzedeq), meaning righteousness, fairness, or justice, and is related to the Hebrew word Tzadik, meaning righteous as an adjective (or righteous individual as a noun in the form of a substantive). Although the word appears 157 times in the Masoretic Text of the Hebrew Bible, typically in relation to "righteousness" per se, its use as a term for "charity" in the above sense is an adaptation of Rabbinic Judaism in Talmudic times.

In the Middle Ages, Maimonides conceived of an eight-level hierarchy of tzedakah, where the highest form is to give a gift, loan, or partnership that will result in the recipient becoming self-sufficient instead of living upon others. In his view, the second highest form of tzedakah is to give donations anonymously to unknown recipients.