AbstractThis article contends that three distinct physical processes control electron transport in conductor‐filled polymer systems. Percolation is required to explain the macroscopic conduction in the disordered medium. Quantum mechanical tunneling (possibly quantum fluctuation augmented) is needed to describe conduction between adjacent conductive particles at the microscopic level. And, thermal expansion is invoked to deduce constituent volume densities and microscopic tunnel lengths. Each of these mechanisms is given a mathematical form. The ansatz is used to predict resistivityvs.temperature and resistivityvs.conductor‐filling fraction functions. Successes and deficiencies of the theory are discussed with respect to experimental data and theoretical considerati