Environmental imperatives are increasingly steering industrial focus toward sustainable materials, positioning fiber-reinforced thermoplastic (FRT) composites as pivotal solutions. These composites confront significant developmental and optimization challenges for structural applications, primarily due to their complex multi-scale reinforcement structures and the nuanced multiphysical phenomena associated with thermoplastic use in manufacturing processes. Building on the groundwork laid by the first part of this special issue, this second part encourages further exploration into the long-term durability, scalability, and holistic performance evaluation of these composites. Such investigations are essential for understanding their long-term applicability and environmental impacts. Additionally, research into the recycling processes and end-of-life strategies for these composites is crucial for enhancing their environmental sustainability. This special issue seeks contributions that explore the tight interrelationships between processing, structure, and performance of FRT composites. It is structured around several key thematic clusters: 1. Composite Material Development: This cluster investigates developments extending the capabilities of these materials in high thermo-mechanical performance, low-density, flame-retardancy, electric or thermal conductivity, piezoelectricity, etc. 2. Process Optimization and Advanced Manufacturing: This cluster focuses on enhancement of manufacturing processes that significantly improve the properties, performance and cost-effectiveness of these materials, vital for broadening their industrial applications and advancing manufacturing efficiencies. 3. Advanced Hybrid Experimental and Numerical Techniques: Contributions under this cluster are expected to introduce advanced modeling and experimental approaches that enhance the predictability and performance of composites. This includes multi-scale mechanical characterizations, interfacial properties between fiber and matrix, the optimization of reinforcements load transfer, etc. 4. Sustainability, Circularity and Environmental Impact: Research in this cluster emphasizes on sustainable development practices, investigating the re-use of recycled materials, the effect of recycling chains of the material properties and the integration of sustainability throughout the lifecycle of composites, underscoring a commitment to environmental stewardship. The insights from these clusters are not only expected to shed light on the current capabilities of FRT composites but also underscore their alignment with global sustainability priorities, highlighting the role of these materials in addressing broader societal challenges. The contributions in this special issue are expected to extend the discourse on material combinations and process optimizations, emphasizing the field’s contribution to environmental responsibility through innovative design and lifecycle management. This second part of the special issue invites the scientific community to engage deeply with these advanced developments and strategic evaluations that could significantly enhance the scientific and practical relevance of fiber-reinforced thermoplastic composites, spurring further innovations in this dynamic field.