Tomás Benjamín Aceval Marín (1845 – July 25, 1900) was a Paraguayan statesman, educator and diplomat.

[1] From 1877 to March 1879 he was Minister Plenipotentiary in special mission in Washington, D.C. and represented the government of Higinio Uriarte in the Chaco Boreal dispute with Argentina, after the Paraguayan War, to the President of the U.S.A. Rutherford B. Hayes.

On February 16, 1887 he negotiated with the Bolivian plenipotentiary Isaac Tamayo,[2] the abortive Aceval-Tamayo Treaty.

[4] He died of Bubonic plague, amidst an epidemic that hit Asuncion.

Benjamín Aceval, a town in the Department of Presidente Hayes in Paraguay is named in his honor.