<p>Green gentrification exacerbates urban socio-spatial inequities generated, paradoxically arising from urban greening initiatives—such as parks and green infrastructure—that initially aim to promote justice. This “green space paradox” refers to how urban green spaces often trigger gentrification, particularly in formal green spaces (FGS) driven by economic interests. In contrast, informal green spaces (IGS) are typically overlooked due to their low financial value. This review investigates the relationship between IGS and gentrification, exploring how IGS mitigate green gentrification through ecosystem services provision. To enrich on IGS’s anti-gentrification potential and guide future management, we propose a conceptual framework addressing the green space paradox. This framework demonstrates how IGS delivers ecosystem services while reducing green gentrification risks to achieve social-ecological trade-offs. First, IGS provides ecosystem services, especially regulating and supporting services, which fill gaps in park-poor areas resulting from the inequitable distribution of green space. Second, IGS prevents gentrification through key attributes: low economic appeal, abundance, high accessibility, community identity formation, and low-cost management. These characteristics enable IGS to support ecological succession, enhance urban resilience, and advance environmental justice by balancing ecosystem services delivery with reduced gentrification risks. </p>