This book chapter provides an exciting and insightful look at the theoretical development of the bioheat transfer models. The energy balance equation and constitutive relations are important parameters for developing theoretical bioheat transfer models. In this chapter, a systematic theoretical development of the constitutive relation and the corresponding bioheat transfer equation is derived under four major headings: Equilibrium, Non-equilibrium, Fractional, and Memory Dependent Bioheat Models. The equilibrium assumptions between tissue and arterial temperature lead to bioheat transport models having relaxation times. In addition, based on the theory of three relaxation time parameters (TPL) constitutive relation, TPL, and the Fractional TPL bioheat transfer model have also been developed. The kernel function of MDD bioheat models depends on the material responses and simulated data strongly depends on the parameters of the kernel function. The present study will be helpful for the medical community for better use of thermal data during thermal treatment planning.