Gamaliel IV (probably late 3rd Century CE) (also known as Gamaliel IV ben Judah II, being the son of the nasiJudah II) was and father of Judah III.
Gamaliel was the president of the Sanhedrin between 270 and 290 CE. However, due to persecution of the Rome, during his presidency the name Sanhedrin was dropped and its authoritative decisions were subsequently issued under the name Beth HaMidrash.
In the Jerusalem Talmud there is a story of Gamaliel's humility, when he was asked a question about the law by Abbahu, Gamaliel speaks of his own ignorance in comparison with Abbahu. Hoshaiah is said to have prevented Gamaliel from introducing into Syria a ruling referring to the tithing of crops.