ConspectusTwo-dimensional (2D) nanomaterials have attracted increasing research interest since mechanically exfoliated graphene was obtained in 2004. The ultrathin thickness and relatively large lateral size of 2D nanomaterials render them various intriguing properties such as compelling electronic properties, ultrahigh specific surface area, excellent mechanical properties, and so on. A wide range of 2D nanomaterials, including graphene and its derivatives, transition metal dichalcogenides (TMDs), metals, etc., have been prepared with different compositions, structures and (crystal) phases. Simultaneously, extensive research efforts have been devoted to exploring the potential applications of these 2D nanomaterials with enhanced performances. Hybridization of two or more nanomaterials to prepare novel composites could efficiently integrate the advantages of the individual components and thus optimize their performances for specific applications. Among various hybridization approaches, the templated synthesis method, i.e., using a presynthesized nanomaterial as a template to direct the growth of a secondary nanostructure, provides an efficient way to prepare composites with high controllability. The ultrathin thickness, large specific surface area, and versatile physiochemical properties of 2D nanomaterials make them ideal templates for constructing composites with desired structures, properties, and functions. Until now, various 2D nanomaterials have been used as templates to grow different kinds of nanomaterials, including metals, metal oxides, metal chalcogenides, metal-organic frameworks (MOFs), etc., to form 2D nanomaterial-templated composites that show potentials in various applications. In this Account, we first briefly introduce the general research background of 2D nanomaterials and the motivation for the preparation of 2D nanomaterial-templated composites. Then we summarize our progress and some other representative work on 2D nanomaterial-templated composites, with a particular emphasis on graphene-templated composites, 2D TMD-templated composites, and 2D metal-templated composites. Specifically, representative examples of the graphene-templated zero-dimensional (0D), one-dimensional (1D), and 2D composites and the emerging graphene-templated van der Waals heterostructures are described. Subsequently, typical 2D TMD-templated composites such as metal oxides, metals, and metal chalcogenides are also presented. In addition, we introduce 2D metal-templated composites and highlight that the crystal phase of the 2D metal template can play an important role in the controlled synthesis of heterostructures. Other composites constructed using 2D metal oxides, metal hydroxides, metal sulfides, and MOFs as templates are also introduced. After that, we demonstrate the potential applications of 2D nanomaterial-templated composites, including electrocatalysis, electronic devices, batteries, and so on. Finally, after a brief summary, our personal insights on the challenges and future research directions in this emerging field are also proposed.