Conventional foundation design approaches often rely on predefined geometries, limiting the exploration of alternative load-transfer mechanisms in wind turbine foundations. This work presents a binary topology optimization framework for the conceptual structural design of wind turbine foundations based on the Topology Optimization of Binary Structures (TOBS) method. The TOBS method employs strictly binary design variables and solves the optimization problem through sequential integer linear programming, enabling a direct and unambiguous soil-foundation representation. The structural response of the coupled foundation-soil system is modeled using the finite element method, with soil–structure interaction explicitly incorporated into the analysis. The sensitivities of the problem are evaluated using semi-automatic differentiation. Both static and dynamic response problems are investigated. Numerical studies under representative wind turbine loading conditions demonstrate that the proposed approach is capable of identifying efficient load-transfer paths governed by the coupled soil–structure response. The results highlight the potential of binary topology optimization as a decision-support tool for early-stage foundation design, contributing to reduced material usage and more efficient infrastructure in wind energy systems.