Lihyan (Arabic: لحيان, Liḥyān; Greek: Lechienoi), also called Dadān or Dedan, was an ancient Arab kingdom that played a vital cultural and economic role in the north-western region of the Arabian Peninsula and used Dadanitic language. The kingdom flourished for at least a century and a half, at some point between the 5th and 1st centuries BC. The Lihyanites ruled over a large domain from Yathrib in the south and parts of the Levant in the north.
In antiquity, the Gulf of Aqaba used to be called Gulf of Lihyan, a testimony to the extensive influence that Lihyan acquired. The term "Dedanite" usually describes the earlier phase of the history of this kingdom since their capital name was Dedan, which is now called Al-'Ula oasis located in northwestern Arabia, some 110 km southwest of Teima, both cities located in modern-day Saudi Arabia, while the term "Lihyanite" describes the later phase. Dadan in its early phase was "one of the most important caravan centers in northern Arabia". It is also mentioned in the Hebrew Bible.