Since their discovery in 1991, carbon nanotubes (CNTs) have found widespread use in various industries, from aerospace to energy, due to their excellent mechanical, thermal, electrical, and tribological properties. Their lightweight nature, small size, incredible tensile strength, and conductivity have made them very popular as reinforcements in metals, polymers, and even finding employment in additive manufacturing. In this review, we provide a rundown of these structures and discuss in detail the numerous methods used to process CNT-reinforced materials, such as chemical vapor deposition (CVD), ball milling, hot pressing, and selective laser melting. The limitations of manufacturing and processing these composites are also discussed, strengthened by the support of different published works. To understand the changes in the properties of these composites in terms of varying parameters such as temperature, CNT length, diameter, etc., an extensive summary is provided, describing several techniques to perform experimental analysis and giving plausible reasons for attributing these changes. Consequently, we explore the specific areas of applications for these CNT-reinforced composites in fields such as aerospace, energy, biomedical, and automobile, and how they can be further processed and changed to allow for more affordable and efficient solutions in the future.