The tropics and subtropics, collectively the Greater Tropics, are home to most of Earth’s biodiversity and humanity, and are undergoing unprecedented transformations driven by global change. In this Review, we assess how alien plants, an underappreciated component of these transformations, interact with other global changes, including land-use shifts, climate change and biotic attrition, to reshape socioecological systems in the Greater Tropics. Whereas many alien plants initially act as passengers of global change, others can become powerful drivers, reconfiguring ecological communities and catalysing novel ecosystem dynamics. Arising changes risk creating homogenized plant communities further disrupted by intense human pressure and social vulnerability. Drawing on insights from community ecology, biogeography and evolutionary theory, we examine the implications of these transformations and the potential for alien plants to both exacerbate and buffer the impact of global change. Given the rapid ecological shifts underway, we highlight the critical need for forwards-looking management that integrates ecological complexity with social realities. We advocate for adaptive, evidence-based frameworks — including nature-based solutions and the resist–accept–direct typology — that support both biodiversity and human well-being. A proactive, inclusive approach to managing alien plants is essential to safeguard socioecological resilience in the Greater Tropics.