Balbinus (Latin: Decimus Caelius Calvinus Balbinus Pius Augustus; c. 165 – 29 July 238), was Roman Emperor with Pupienus for three months in 238, the Year of the Six Emperors.

Not much is known about Balbinus before his elevation to emperor. It has been conjectured that he descended from Publius Coelius Balbinus Vibullius Pius, the consul ordinarius of 136 or 137, and wife Aquilia. If this were true, he was also related to the family of Q. Pompeius Falco, which supplied many politicians of consular rank throughout the 3rd century, and to the 1st-century politician, engineer and author Julius Frontinus, as well as a descendant of a first cousin of Trajan. He was a patrician from birth, and was the son (either by birth or adoption) of ... Caelius Calvinus, who was legate of Cappadocia in 184. He was one of the Salii priests of Mars. According to Herodian he had governed provinces, but the list of seven provinces given in the Historia Augusta, as well as the statement that Balbinus had been both Proconsul of Asia and of Africa, are likely to be mere invention. He had certainly been twice consul; his first consulate is not certainly known but is believed to have been about 203 or in July 211; he was consul for the second time in 213 as colleague of Caracalla, which suggests he enjoyed that emperor's favour.