In today’s environment, digital technology and digital computing are unavoidable components of the creation of electronic gadgets. Quantum-dot cellular automata, or QCA, is a new paradigm for realizing digital logic on the nanoscale. QCA technology is a type of nanotechnology that is used to construct computational circuits. Due to its low latency and area consumption, it can be a promising technique for overcoming CMOS limitations at the nanoscale. Also, fault-tolerant circuits ensure circuit resilience using dependable circuits in this technology. The multiplexer is one of the essential circuits in computer logic. In the most widely used circuits, the multiplexer is an important and primary component. Therefore, in this paper, using the micro-level polarization of QCA, we attempt to develop a fault-tolerant multiplexer architecture. The study employs fault-tolerant majority gates to create a fault-tolerant 2:1 multiplexer. QCADesigner develops and simulates the proposed multiplexer. The results indicate the efficiency of the proposed design in comparison with other designs.