<p>A framework of the ternary composite or more than ternary composite materials for gas-/vapor-sensing applications is presented in this review article. The synthesis aspects of different ternary composites and beyond have been materialized with their technological evolution and limitations. A comparative performance of binary/ternary and/or beyond composite materials-based different sensor configurations towards gases/vapor is discussed with special emphasis on sensor response, optimum temperature, response time, recovery time, selectivity, and stability. Aspects of reducing particle size, incorporation of foreign elements, variation of sensing layer thickness, temperature, and biasing conditions have been comprehensively reviewed. Engineering approaches for improving the critical issues in ternary and beyond materials devices, such as variation of operating temperature, biasing, long-term stability, and poor reliability have been demonstrated with possible solutions to the technological limitations. In a nutshell, the better sensing performance of the ternary and beyond ternary than that of the binary components has been framed considering the adsorption–desorption isotherm, sticking probability, Fermi level pinning, and the concept of the HOMO–LUMO model under different ambient conditions.</p>