The senior rock (also called spirit rock) is a rural and suburban United States tradition in which youth, often a high school senior class, paint a prominent local rock with class colors, graduating year, or names of the members of the class.^[1] A rock at Northwestern University is said to have "inches of paint after 80 years of the tradition".^[2] The tradition may have started in the 1950s or 1960s at universities and high schools.^[3]

Rocks are usually indigenous but they can be delivered to the school as a specifically designated senior rock.^[4] In at least one case a rock has been donated from one graduating class to a following class of seniors.^[5] A senior rock at Olympia High School was "dumped" from a local quarry after another one had been removed.^[6]

Council Rock High School North in Bucks County, Pennsylvania, is named for a rock which is frequently painted.