AimsPlant-plant interactions play a pivotal role in shaping community structure and regulating nutrient cycling through modulating both intra- and interspecific resource allocation. These interactions largely impact ecosystem services, particularly in the context of global climate change. To address this, our review synthesizes global research on plant-plant interactions, evaluates current progress, and identifies key knowledge gaps to guide future research.MethodsWe analyzed 346 peer-reviewed articles from the Web of Science to quantify intra- and interspecific interactions. Research trends were evaluated based on spatial and temporal patterns, plant functional groups, plant organs of focus (e.g., roots, leaves), and environmental drivers (e.g., atmospheric, soil, and biological factors). This systematic evaluation highlights key research priorities and biases.ResultsResearch efforts are geographically concentrated in China and the United States, with a strong focus on grasslands. Taxonomically, Poaceae, Leguminosae, and Asteraceae are disproportionately represented. Despite the substantial body of research, significant geographical and ecosystem biases persist, with ecosystems like tropical, alpine, and desert regions being underrepresented. Aboveground interactions and environmental factors such as light intensity and soil moisture around trees, as well as rhizosphere soil nutrients in grasslands and crops, dominate the focus of studies. However, the essential roles of roots and the rhizosphere in nutrient uptake, water transport, and microbial interactions remain underexplored. It is crucial for ecological research to broaden the scope by incorporating a wider range of ecological factors, exploring underexplored ecosystems, and achieving a more balanced focus on both aboveground and belowground dynamics.ConclusionTo advance ecological theory and application, future research must adopt a more holistic framework that integrates underrepresented ecosystems (e.g., tropical, alpine, desert) and balances the study of above- and belowground dynamics. Expanding research to include root-rhizosphere interactions, microbial symbioses, and multifactorial environmental drivers (e.g., temperature gradients, CO2 levels, biotic stressors) will enhance the predictive capacity for ecosystem responses to global change. Bridging these knowledge gaps will not only enhance our understanding of plant ecology but also inform better conservation strategies and ecosystem management practices in the face of ongoing environmental changes.