Kate Holladay Claghorn (c. 1864 – May 22, 1938) was an American sociologist, economist, statistician, legal scholar, and Progressive Era activist, who became one of the founders of the National Association for the Advancement of Colored People.

[21] In her 1923 book, The Immigrants' Day in Court, Claghorn argued that the legal aid available at the time was inadequate, focusing primarily on legal minutiae rather than on understanding the actual issues affecting their clients, and that it inappropriately excluded female attorneys from serving.

[26] Writing about this book in 2003, British historians Kristofer Allerfeldt and Jeremy Black called it "the one significant contemporary study of the immigrant and the American legal system".

[9] In 1909 Claghorn was one of 60 signers of the "Call for the Lincoln Emancipation Conference to Discuss Means for Securing Political and Civil Equality for the Negro",[11] which became the founding document of the National Association for the Advancement of Colored People.

[28] Claghorn chaired a committee of the American Institute of Criminal Law and Criminology on connections between crime and immigration, which produced its report in 1917.