Mário Ferreira dos Santos (January 3, 1907 – April 11, 1968) was a Brazilian philosopher.
Born in Tietê, São Paulo, Ferreira dos Santos was raised in Pelotas, Rio Grande do Sul, and graduated in Law and Social Sciences at the Federal University of Rio Grande do Sul.
A prolific writer and thinker, Ferreira dos Santos published in less than fifteen years the 45-volume Encyclopedia of Philosophical and Social Sciences.