João Mangabeira (26 June 1880 – 27 April 1964) was a Brazilian jurist, politician and writer.

According to Federal jurist and politician Paulo Brossard: "When the annual session of the jury started, a poor defendant went on trial without a lawyer.

As soon as the prosecutor concluded the indictment, the young defense lawyer, appointed minutes before, shattered the charge, pointing out contradictions, correcting names, indicating process pages that he did not handle at all.

The defendant was acquitted ... and, thereafter, the city began to trust the lawyer who was no more than a child, and his office started to have clients."

As deputy for the Constitutional Assembly of 1934, and his opposition to the Estado Novo dictatorship (Vargas Era) landed Mangabeira in prison for 15 months.