Khan Tervel () also called "Tarvel", or "Terval", or "Terbelis" in some Byzantine sources, was the khan of Bulgaria during the First Bulgarian Empire at the beginning of the 8th century. In 705 Emperor Justinian II named him caesar, the first foreigner to receive this title. He was raised a pagan like his grandfather Khan Kubrat. but was later possibly baptised by the Byzantine clergy. Tervel played an important role in defeating the Arabs during the siege of Constantinople in 717–718.