Metal film capacitors are ubiquitous components in modern electronics, playing an important role in energy storage, filtering, and voltage regulation. However, their performance and reliability can be reduced by partial electrical breakdowns caused by defects in the dielectric material. An attempt to partially mitigate this problem is the use of self-healing capacitors. The self-healing phenomenon significantly increases the service life of the device. This review presents a comprehensive analysis of the currently known aspects and mechanisms of self-healing in metal film capacitors. The role of the self-healing phenomenon in increasing the number of operating cycles of a dielectric capacitor is discussed. The molecular processes underlying significantly different self-healing potentials of dielectric polymers are verified. The review is addressed to specialists in electrical engineering.