William John Youden (April 12, 1900 – March 31, 1971) was an Australian-born American statistician who formulated new statistical techniques in statistical analysis and in design of experiments.

He developed the "Youden square", an incomplete block design developed from a 1937 paper, "Use of Incomplete Block Replications in Estimating Tobacco Mosaic Virus".

[1][2][3][4] He devised Youden's J statistic as a simple measure summarising the performance of a binary diagnostic test.

[6] The American Statistical Association bestows the W. J. Youden Award in Interlaboratory Testing to authors "of publications that make outstanding contributions to the design and/or analysis of interlaboratory tests or describe ingenious approaches to the planning and evaluation of data from such tests."

[7] In 1967, Youden served as president of the Philosophical Society of Washington, a science organization.