The study of heat transfer in composite materials is crucial for the design and analysis of advanced engineering systems, including aerospace structures, electronic devices, and energy storage systems. Traditional numerical methods such as finite element and finite difference methods often require discretization of the entire domain, leading to high computational costs, especially for problems involving complex geometries and infinite or semi-infinite domains. The Boundary Element Method (BEM), based on integral equation formulations, offers a powerful alternative by reducing the problem dimensionality and focusing computations on boundaries and interfaces. This article presents an in-depth review of integral equation modeling for heat transfer in composite materials using BEM. We discuss the mathematical formulation, implementation strategies, and the unique advantages of BEM for multi-phase and multi-scale composite systems. Numerical results and case studies highlight the accuracy and efficiency of BEM in predicting temperature distributions and heat fluxes in heterogeneous media. The discussion covers current challenges and future prospects for BEM in advanced heat transfer modeling.