A ruler is a device used to measure distances or draw straight lines.
Ruler may also refer to: A person who wields significant or total political power Ruler (film), a 2019 Indian Telugu-language action film Ruler (gamer), stage name of League of Legends player Park Jae-hyuk Ruler (horse), a racehorse Golomb ruler, comprises a series of marks such that no two pairs of marks are the same distance apart Slide rule, a mechanical analog computer "Ruler", a song by Marnie Stern from This Is It and I Am It and You Are It and So Is That and He Is It and She Is It and It Is It and That Is That Ruler, a character from the sixth season of Battle for Dream Island, an animated web series
See also Rule (disambiguation)