No true Scotsman is an informal logical fallacy, an ad hoc attempt to retain an unreasoned assertion. When faced with a counterexample to a universal claim, rather than denying the counterexample or rejecting the original universal claim, this fallacy modifies the subject of the assertion to exclude the specific case or others like it by rhetoric, without reference to any specific objective rule.

The use of the term was advanced by philosopher Antony Flew in his 1975 book Thinking About Thinking: Do I sincerely want to be right?.

When the statement "all A are B" is qualified like this to exclude those A which are not B, this is a form of begging the question; the conclusion is assumed by the definition of "true A".

A simple rendition would be:

An example of a political application of the fallacy could be in asserting that "no democracy starts a war" (which is also a Straw man), then distinguishing between mature or "true" democracies, which never start wars, and "emerging democracies", which may start them. At issue is whether or not something labeled as an "emerging democracy" is actually a democracy or something in a different conceptual category.

True Scotsman is a humorous term used in Scotland for a man wearing a kilt without undergarments. Though the tradition originated in the military, it has entered Scottish lore as a rite, an expression of light-hearted curiosity about the custom, even as a subversive gesture.

Kilts have been traditionally worn without undergarments since their use as part of Scottish military uniform, leading to the invention of such expressions as "go regimental" or "military practice" for wearing no underwear. On the Western Front during the First World War, some Sergeants Major reportedly had mirrors tied to the end of golf clubs or walking sticks to inspect up and under the kilt at parade inspection. However, in 1940 the kilt was retired from combat due to the vulnerability of bare skin to chemical agents, although it was retained as the formal dress uniform of the regiments. In the 1950s, kilted soldiers on parade would be checked by the Sergeant Major using a mirror on the barracks floor. In 1997, a Black Watch soldier received wide press exposure, because of windy conditions during a military ceremony in Hong Kong.

True may refer to: