In fluid mechanics, the Cheerios effect is the tendency for small wettable floating objects to attract one another.

An example of the Cheerios effect is the phenomenon whereby breakfast cereal tends to clump together or cling to the sides of a bowl of milk.

Writing in the American Journal of Physics, Dominic Vella and L. Mahadevan of Harvard University discuss the cheerios effect and suggest that it may be useful in the study of self assembly of small structures.