Nanomaterials have become an established area of academic research and have gained commercial importance due to their valuable physicochemical properties, such as large surface area, high mechanical strength as well as unique optical and electrical features. Numerous nanosize architectures have been researched and reported to date including quantum dots, fullerenes, nanorods, nanowires, nanofibers, nanosheets, nanowalls, nanocoils, and nanoballs, etc. Among these materials, nanofibers are extremely valuable morphologies used across many industries spanning from textile to medical applications and beyond. This review article focuses on the various works and reports of MgO-based applications and its overlap with nanofiber-based structures. Comprehensive review of the growing number of reports to date provides a unified resource for researchers going forward. As the acceptance and broader set of applications continues its exponential growth in commercial and academic output, it is envisaged that MgO-based composites will play a central part in many future reports of nanofibrous composites and other composite architectures, e.g., particle-reinforced composites, metal matrix composites, ceramic matrix composites, etc., due to the wide variety of applications to which MgO is suited, as well as other peripheral properties such as cost, availability, ease-of-handling, and use, etc. Indeed, despite the many preliminary reports to date, there remains a great deal yet to discover and optimize for such systems.