Early Bulgarian rulers possibly used the title Kanasubigi (khan), later knyaz (prince) for a brief period, and subsequently tsar (emperor). The title tsar, the Bulgarian form of the Latin Caesar, was first adopted and used in Bulgaria by Simeon I, following a decisive victory over the Byzantine Empire in 913. It was also used by all of Simeon I's successors until the fall of Bulgaria under Ottoman rule in 1396. After Bulgaria's liberation from the Ottomans in 1878, its first monarch Alexander I adopted the title knyaz, or prince. However, when de jure independence was proclaimed under his successor Ferdinand in 1908, the title was elevated to the customary tsar once more. The use of tsar continued under Ferdinand and later under his heirs Boris III and Simeon II until the abolition of monarchy in 1946.
While the title tsar was translated as "emperor" in the First and Second Bulgarian Empires, it was translated as "king" in modern Bulgaria.
In the few surviving medieval Bulgarian royal charters, the monarchs of Bulgaria styled themselves as "In Christ the Lord Faithful Emperor and Autocrat of all Bulgarians" or similar variations, sometimes including “... and Romans, Greeks, or Vlachs".
This list does not include the mythical Bulgar rulers and the rulers of Old Great Bulgaria listed in the Nominalia of the Bulgarian khans as well as unsuccessful claimants to the throne who are not generally listed among the Bulgarian monarchs.
There is one living former Bulgarian Tsar: Simeon Sakskoburggotski.