This Perspective illustrates how the presence of internal and external electric fields can affect catalytic activity and selectivity, with a focus on heterogeneous catalysts. Specifically, experimental investigations of the electric field influence on catalyst selectivity in pulse field mass desorption microscopes, scanning-tunneling microscopes, probe-bed-probe reactors, continuous-circuit reactors, and capacitor reactors are described. Through these examples, we show how the presence of theelectric field, whether can be externally applied or intrinsically be unintentionally present, can affect the behavior of in a wide number of materials that are relevant to catalysis. We review some of the theoretical methods that have been used to elucidate the influence of external electric fields on catalytic reactions, as well as the application of such methods to selective methane activation. In doing so, we illustrate the breadth of possibilities in field-assisted catalysis.