Halide　perovskites　(HPs),　emerging　as　a　noteworthy　class　of　semiconductors,　hold　great　promise　for　an　array　of　optoelectronic　applications,　including　anti-counterfeiting,　light-emitting　diodes　(LEDs),　solar　cells　(SCs),　and　photodetectors,　primarily　due　to　their　large　absorption　cross　section,　high　fluorescence　efficiency,　tunable　emission　spectrum　within　the　visible　region,　and　high　tolerance　for　lattice　defects,　as　well　as　their　adaptability　for　solution-based　fabrication　processes.　Unlike　luminescent　HPs　with　band-edge　emission,　trivalent　rare-earth　(RE)　ions　typically　emit　low-energy　light　through　intra-4f　optical　transitions,　characterized　by　narrow　emission　spectra　and　long　emission　lifetimes.　When　fused,　the　cooperative　interactions　between　HPs　and　REs　endow　the　resulting　binary　composites　not　only　with　optoelectronic　properties　inherited　from　their　parent　materials　but　also　introduce　new　attributes　unattainable　by　either　component　alone.　This　review　begins　with　the　fundamental　optoelectronic　characteristics　of　HPs　and　REs,　followed　by　a　particular　focus　on　the　impact　of　REs　on　the　electronic　structures　of　HPs　and　the　associated　energy　transfer　processes.　The　advanced　synthesis　methods　utilized　to　prepare　HPs,　RE-doped　compounds,　and　their　binary　composites　are　overviewed.　Furthermore,　potential　applications　are　summarized　across　diverse　domains,　including　high-fidelity　anticounterfeiting,　bioimaging,　LEDs,　photovoltaics,　photodetection,　and　photocatalysis,　and　conclude　with　remaining　challenges　and　future　research　prospects.