Regret may refer to:

• Regret is an intelligent (and/or emotional) dislike for personal past acts and behaviours. Regret is distinct from guilt, which is a deeply emotional form of regret —one which may be difficult to comprehend in an objective or conceptual way. In this regard, the concept of regret is subordinate to guilt in terms of its "emotional power". By comparison, shame typically refers the social, (rather than personal) aspect of guilt or (in minor context) regret as imposed by the society or culture (enforcement of ethics, morality), which has substantial bearing in matters of (personal and social) honor.

• "Regret" was also the first single from the album Republic, by New Order
• Regret (horse) - a champion racehorse
• Regret (Decision theory) - the difference between Expected Loss and Actual Loss; or from Microeconomics defined as net cost minus the least cost which, in hindsight, would have been incurred by a different decision sequence.