Created by RobCo, protectron robots were designed (as their name suggests) for protection, although they can also be seen being used in a manual labor role as well. Typically used in office-type settings, their secondary programming is modular, making them useful as greeters, ticket collectors, bartenders, celebrity or historical figure impersonators, even sexual partners. In terms of combat, protectrons are usually weak and easy to defeat, because of their weak weapons and slow movement speed.

In Fallout 4, Protectrons are found in charging pods attached to terminals that must sometimes be hacked to activate them. The terminal software allows for different "personalities" to be uploaded to the unit, which changes the unit's voice dialogue and weapons loadout. The choices are: Default, Subway Steward, Construction Worker, MedIcal Responder, Firefighter, and Law Enforcement.

Some attributes of the protectron's looks were derived from 1950's comic books, which keeps with Fallout's overall retrofuturistic theme.