Thermal conduction in polymeric materials and across interfaces is of considerable scientific and tech-nological importance nevertheless only very few studies are available without elucidating the detailedrecent understandings of thermal transport in polymers and its composites. This limits our present under-standing of science for creating better thermal pathways for efficient thermal management applications.This comprehensive review attempts to offer a fundamental knowledge base to elucidate energy transferpathways, mechanisms, various factors governing heat conduction in polymers and interfaces along withidentification of various fillers, matrix and techniques for the modification of interfaces to enhance heatconduction. First theoretical basis is used to establish fundamental of heat transfer in molecule, bulkpolymeric material and polymer composites and interfaces and then various detailed factors governingthe thermal transport of polymer and interfaces are presented. Various recent techniques to improvethermal conductivity of polymer and interfaces are illustrated through examples and case studies. Apartfrom the traditional technologies (filler and matrix), the recent developments in non-conventional tech-nologies like polymer blends, polymer/inorganic and polymer/organic hybrids, etc. are also presented. Weexpect that various future studies may benefit from knowledge gained in this detailed in-depth reviewon thermal transport in polymer and interfaces.