Heterocycles are an important class of compounds that are widely used in pharmaceuticals, agrochemicals, dyes, and materials. Multicomponent reactions (MCRs) offer efficient synthetic routes for producing these complex structures. The search for effective and sustainable catalytic processes in organic synthesis has led to the exploration of various nanomaterials as potential catalysts. To this end, carbon nanotubes (CNTs) have recently emerged as promising heterogeneous catalysts for the MCR synthesis of heterocycles due to their unique properties, which include high surface area and reactivity, tunable surface chemistry, excellent electrical conductivity, recyclability, and exceptional thermal and chemical stability. This review provides a comprehensive analysis and overview of the use of CNTs as catalysts for synthesizing heterocycles via MCRs and their advantages.