A bar mitzvah (masc.) or bat mitzvah (fem.) is a coming-of-age ritual in Judaism. According to Jewish law, before children reach a certain age, the parents are responsible for their child's actions. Once Jewish children reach that age, they are said to "become" b'nai mitzvah, at which point they begin to be held accountable for their own actions. Traditionally, the father of a bar or bat mitzvah offers thanks to God that he is no longer punished for his child's sins.

Coming of age is a young person's transition from being a child to being an adult. The specific age at which this transition takes place varies between societies, as does the nature of the change. It can be a simple legal convention or can be part of a ritual or spiritual event.