3D printing has evolved quickly from rapid prototyping to true mass production. This is reflected in the use of the term additive manufacturing (AM) to emphasize the use of the technology in actual manufacturing of high‐value products and finished goods. Consequentially, the requirements on the materials and processes have become more stringent and challenging to satisfy. Furthermore, various manufacturing industries have their own unique sets of requirements, and these are difficult if not impossible to satisfy with neat polymers alone. Therefore, additives are playing an increasingly critical role for satisfying material requirements for AM applications. In this article, challenges are identified that will need to be addressed as AM matures toward manufacturing applications. These include speed of production, mechanical performance and durability of the products, their interaction with the environment, and readiness for manufacturing. The use of additives to overcome these challenges is discussed in terms of current trends and with the help of specific examples. These include, but are not limited to, reinforcements, thermal stabilizers, antioxidants, and flame retardants to improve performance and meet thermal, environmental, and flammability requirements in demanding applications like aerospace, defense, and automotive. Further, colors, pigments, and dyes are needed for aesthetics. Bioactive or bioinert materials are needed for specific medical applications, and electrically dissipative or thermally conductive materials are often needed for electronics applications. This article provides a critical look at the current state of AM and how the roles of additives in AM are expected to expand, including identification of future opportunities. As 3D printing continues to be used in more and more challenging applications, the ability to meet requirements depends on the use of highly engineered materials incorporating additives, such as flow enhancers, fiber reinforcement, thermally or electrically functional materials, and antioxidants.