Prince Yaropolk I Sviatoslavich (alternative spelling Iaropolk) (? - 980) was a young and rather enigmatic ruler of Kiev between 972 and 980.

Yaropolk was given Kiev by his father Sviatoslav I, who left on a military campaign against the Danube Bulgars. Soon after Sviatoslav's death, however, civil war soon began between Yaropolk and his brothers. According to one chronicle, Yaropolk's brother Oleg killed Lyut, the son of Yaropolk's chief adviser and military commander Sveneld . In an act of revenge and at the insistance of Sveneld, Yaropolk went to war against his brother and killed him. Then, Yaropolk sent his men to Novgorod, from which his other brother Vladimir had fled on receiving the news about Oleg's death. Yaropolk became the sole ruler of Rus.

In 980, Vladimir returned with the Varangian mercenaries and attacked Yaropolk. On his way to Kiev, Vladimir seized Polotsk due to the fact that Rogneda, daughter of the Polotsk chieftain Rogvolod , had chosen Yaropolk over him. Vladimir forced Rogneda to marry him. Then, Vladimir seized Kiev with the assistance from a boyar Blud, who had become Yaropolk's chief adviser upon the death of Sveneld. Blud betrayed Yaropolk by advising him to flee from Kiev and go into retreat in a town of Rodnya at the mouth of the Ros River . Vladimir sieged Rodnya and forced starving Yaropolk to negotiate. Yaropolk trusted Blud and his brother's promises of peace and left for Vladimir's headquarters, where he would be killed in an ambush by two Varangians.

As for contemporary foreign sources, they mention a mission sent to Kiev from Prague that converted the ruling prince to Christianity. It has been suggested that Yaropolk went through some preliminary rites of baptism, but was murdered by his pagan half-brother (whose own rights to the throne were questionable) before he could be formally received in the Christian faith. Any information on Yaropolk's baptism according to the Latin rite would be suppressed by later Orthodox chroniclers, zealous to keep Vladimir's image of the Russian Apostle untarnished for succeeding generations.