The induced interfacial polarization mechanism invoked to explain electroviscosity requires a direct relationship between the rheological and electrical properties of an electroviscous system. Static and dynamic measurements of the electric and dielectric properties of electroviscous silica dispersions were made to study these relationships. An electrokinetic potential and conductivity and a small dc power output that depend upon shear rate were observed. Electroviscous fluids under shear exhibit the characteristics of small electric cells. Shear‐induced desorption of weakly held charge carriers out of the double layer is suggested to explain these effects.On application of an external electric field, electroviscosity appears at the onset of current flow. Dielectric measurements under zero‐shear conditions show that the medium in contact with the disperse phase is essentially a low‐dielectric‐constant vehicle while the particles are composites having higher dielectric constants, thereby facilitating interfacial polarization. Anomalous dispersion occurs under zero‐shear conditions at low frequencies as expected on the basis of the proposed interfacial polarization mechanism. Simultaneous dielectric‐constant, loss, and electroviscosity measurements under shear conditions correlate with the effects of changing shear rate, field strength, temperature, and frequency. Increasing temperatures promote polarization while shear stresses transverse to the direction of the applied field perturb the field‐induced polarization. When an electroviscous dispersion is subjected to both mechanical shearing and an external electric field, a dynamic equilibrium is established between the rheological and electrical properties of the system.