Secular ethics is a branch of moral philosophy in which ethics is based solely on human faculties such as logic, empathy, reason or moral intuition, and not derived from belief in supernatural revelation or guidance—the source of ethics in many religions. Secular ethics refers to any ethical system that does not draw on the supernatural, and includes humanism, secularism and freethinking. A classical example of literature on secular ethics is the Kural text, authored by the ancient Tamil Indian philosopher Valluvar.

Secular ethical systems comprise a wide variety of ideas to include the normativity of social contracts, some form of attribution of intrinsic moral value, intuition-based deontology, cultural moral relativism, and the idea that scientific reasoning can reveal objective moral truth (known as science of morality).

Secular ethics frameworks are not always mutually exclusive from theological values. For example, the Golden Rule or a commitment to non-violence, could be supported by both religious and secular frameworks. Secular ethics systems can also vary within the societal and cultural norms of a specific time period.