Tzachas (, Tzachas), also known as Chaka Bey () or Emir Chaka of Smyrna, was an 11th-century Seljuk Turkish military commander who ruled an independent state based in Smyrna (present day Izmir). Tzachas was taken as a prisoner during a war with the Byzantine Empire by Emperor Nikephoros III Botaneiates. The emperor took an interest in the youth and brought him to live in the palace. He was granted the title of protonobilissimus.