Layered transition metal dichalcogenide (LTMD)/carbon nanocomposites obtained by incorporating conductive carbons such as graphene, carbon nanotubes (CNT), carbon nanofibers (CF), hybrid carbons, hollow carbons, and porous carbons exhibit superior electrochemical properties for energy storage and conversion. Due to the incorporation of carbon into composites, the LTMD/carbon nanocomposites have the following advantages: (1) highly efficient ion/electron transport properties that promote electrochemical performance; (2) suppressed agglomeration and restacking of active materials that improve the cycling performance and electrocatalytic stability; and (3) unique structures such as network, hollow, porous, and vertically aligned nanocomposites that facilitate the shortening of the ion and electrolyte diffusion pathway. In this context, this review introduces and summarizes the recent advances in LTMD/carbon nanocomposites for electrochemical energy-related applications. First, we briefly summarize the reported synthesis strategies for the preparation of LTMD/carbon nanocomposites with various carbon materials. Following this, previous studies using rationally synthesized nanocomposites are discussed based on a variety of applications related to electrochemical energy storage and conversion including Li/Na-ion batteries (LIBs/SIBs), Li-S batteries, supercapacitors, and the hydrogen evolution reaction (HER). In particular, the sections on LIBs and the HER as representative applications of LTMD/carbon nanocomposites are described in detail by classifying them with different carbon materials containing graphene, carbon nanotubes, carbon nanofibers, hybrid carbons, hollow carbons, and porous carbons. In addition, we suggest a new material design of LTMD/carbon nanocomposites based on theoretical calculations. At the end of this review, we provide an outlook on the challenges and future developments in LTMD/carbon nanocomposite research.