Jovan Vladimir or John Vladimir was the ruler of Duklja, the most powerful Serbian principality of the time, from around 1000 to 1016. He ruled during the protracted war between the Byzantine Empire and the Bulgarian Empire. Vladimir was acknowledged as a pious, just, and peaceful ruler. He is recognized as a martyr and saint, with his feast day being celebrated on 22 May.

Jovan Vladimir had a close relationship with Byzantium but this did not save Duklja from the expansionist Tsar Samuel of Bulgaria, who attacked Duklja around 997, John Vladimir retreated to the inaccessible mountain areas in the vicinity of Shkodër. Samuel conquered the principality around 1010 and took Vladimir prisoner. A medieval chronicle asserts that Samuel's daughter, Theodora Kosara, fell in love with Vladimir and begged her father for his hand. The tsar allowed the marriage and returned Duklja to Vladimir, who ruled as his vassal. Vladimir took no part in his father-in-law's war efforts. The warfare culminated with Tsar Samuel's defeat by the Byzantines in 1014 and death soon after. In 1016, Vladimir fell victim to a plot by Ivan Vladislav, the last ruler of the First Bulgarian Empire. He was beheaded in front of a church in Prespa, the empire's capital, and was buried there.