As one of the most promising optoelectronic materials, polymers that contain phosphorescent IrIII complexes have attracted more and more interest in recent years. They are a class of well‐known electroluminescent materials with excellent performance. So far, efficient green‐, red‐, and white‐emitting polymer light‐emitting diodes based on polymers with on‐chain IrIII complexes have been realized successfully. For the realization of this class of polymer material, IrIII complexes (as energy guest) can be introduced into the main‐chain or side‐chain of polymers (as energy host). In this article, we summarize the design principles, synthetic routes, structure–property relationships, and applications in optoelectronic devices of polymers that contain phosphorescent IrIII complexes.