Jaromir, Duke of Bohemia, was the second son of Boleslaus II the Pious. (Died November 1035). In 1003 he rebelled against his elder brother Boleslaus III, but was unable to secure the throne which was subsequently taken by Boleslaus the Brave, King of Poland. Jaromir and his brother Oldrich then sought military backing from the German King Henry II. At Merseburg, Jaromir promised to hold Bohemia as a vassal of Henry. This action definitively placed Bohemia within the jurisdiction of the Holy Roman Empire.

In 1004 Jaromir occupied Prague with a German army and made himself Duke. The state he regained was a small one, as Polish forces still held Moravia, Silesia and Lusatia. Jaromir's reign - like so many of the other early Czech rulers - was a struggle to regain the lost lands. In 1012 Jaromir was dethroned by Oldrich, and forced once again into exile. In a surprise campaign, Jaromir in turn managed to depose Oldrich (1033) but his second reign was shortlived. A year later Oldrich was restored by his son Bretislav I. Jaromir was imprisoned at Lysa and died in 1035, a year after his brother.