Plasmonic　nanoparticles　and　their　assemblies　have　been　widely　used　in　biosensing,　optical　imaging,　and　biomedicine　over　the　past　few　decades.　Especially　in　the　field　of　radiotherapy,　the　physicochemical　properties　of　high-Z　plasmonic　nanomaterials　endow　them　with　the　ability　to　sensitize　radiotherapy.　Compared　with　single　particles,　the　assembled　structure　with　tunable　properties　leads　to　versatile　applications　in　drug　delivery　and　cancer　treatment.　In　this　review,　we　focus　on　plasmonic　nanoparticles　and　their　assemblies　for　cancer　radiotherapy.　First,　the　sensitization　mechanism　of　plasmonic　radiosensitizers　is　briefly　introduced.　Subsequently,　the　recent　progress　in　cancer　radiotherapy　is　systematically　discussed　according　to　the　structure　and　shape　classification.　Finally,　the　current　challenges　and　future　perspectives　in　this　field　are　also　discussed　in　detail.　©　2023　Elsevier　B.V.