<p>Understanding how phylogenetic relatedness (pre-adaptation hypothesis and Darwin’s naturalization hypothesis) and trait similarity (limiting similarity hypothesis) between native and invasive alien species influence community reassembly has become an increasingly important focus of biological invasion research. Although many studies have tackled these topics—spanning diverse ecosystems, organisms, methods, and goals—findings on phylogenetic relatedness and trait similarity are highly variable and often difficult to generalize. This variability underscores the importance of a systematic and quantitative analysis of research aimed at understanding the role of phylogenetic relatedness and trait similarity between native and invasive alien species in invasion outcomes across taxa, ecosystems, and scales. Here, through a literature search in the Web of Science database, comprehensive bibliometric analysis, and thematic synthesis, we provide a clear overview of the current state of phylogenetic relatedness and trait similarity research pertinent to biological invasion. We identified 774 articles for screening, of which 251 were selected for systematic and bibliometric analysis. The analysis revealed that most studies focused on grassland ecosystems, followed by forests, shrublands, and deserts. In aquatic ecosystems, most studies were conducted in freshwater systems. Plants were the most frequently investigated taxa, followed by insects (in the context of plant–insect interactions), fish, and ants. Thematic synthesis revealed mixed findings on the role of phylogenetic relatedness and trait similarity in invasion success. Despite their central role in community assembly, the findings of this study emphasize their context-dependent role in shaping invasion outcomes.</p>