This chapter provides a deep study of the use of terpenes, for enhancing the properties of biopolymers such as polylactic acid (PLA) and polyhydroxyalkanoates (PHAs). Terpenes and terpenoids are present in many plants as essential oils. With the growing environmental concern about developing sustainable alternatives to petroleum-based plastics, biobased polymers like PLA and PHAs are emerging as significant candidates to substitute the traditional materials due to their biodegradability. However, their applications, particularly in food packaging due to material limitations such as rigidity and brittleness. Terpenes and terpenoids are natural solution to these challenges by serving as bio-based plasticizers into the polymer matrices of PLA and PHAs. Their incorporation leads to a modification of the polymers’ structure that improves flexibility and enhancing mechanical properties. This chapter shows how terpenes lower the glass transition temperature (Tg) of these biopolymers and increase their ductility, making them more suitable for a broader range of applications, especially in the packaging industry where material flexibility and strength are crucial. Moreover, the utilization of terpenes aligns with the increasing demand for eco-friendly polymer materials, improving the performance of PLA and PHAs but at the same time maintaining their environmentally sustainable profile. By enabling the production of more versatile and biodegradable polymers, terpenes are positioned as key contributors for the evolution of the biopolymer industry. This chapter highlights the potential of terpenes in creating sustainable, flexible materials for future applications, marking a significant step towards reducing the environmental footprint of industrial sectors such as the packaging sector.