This study presents the first systematic literature review on the Physical Internet (PI) using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework. A significant gap exists in the current literature regarding how PI can transform traditional logistics systems into sustainable models, which serves as the core motivation for this research. The review addresses two primary research questions: (a) identifying current trends in PI-related research, and (b) uncovering the key barriers hindering PI adoption. A total of 275 articles were initially retrieved from Web of Science and ScienceDirect, covering the period from 2019 to 2025. After applying inclusion criteria, 50 studies were selected for analysis. Findings reveal a growing academic interest in PI. Major barriers to its adoption include lack of standardization, insufficient government policy support, high initial investment costs, and concerns over data security. This review offers a foundational synthesis to guide future academic inquiry and practical strategies for overcoming challenges in PI implementation. The scope of this study is limited to the defined time horizon.