Urban ecosystems, though hubs of human activity and biodiversity, are increasingly threatened by the proliferation of invasive plant species, particularly in fully urbanized regions like Chandigarh, India. This chapter delves into the complex ecological, socio-economic, and health-related impacts posed by these species in an urban context. Chandigarh, renowned for its planned urban landscape and green infrastructure, has paradoxically become a hotspot for numerous invasive species, including Ageratum conyzoides, Broussonetia papyrifera, Lantana camara, Leucaena leucocephala, Mesosphaerum suaveolens, Neltuma juliflora, Parthenium hysterophorus, Pontederia crassipes, Ricinus communis, etc. These species not only outcompete native flora through aggressive reproduction, allelopathy, and ecological plasticity, but also alter soil composition, disrupt trophic interactions, and impair urban water systems. The study documents the patterns of invasion, ecological traits, and dispersal mechanisms of these species, with a focus on localized case studies within Chandigarh. It further assesses the profound implications for urban biodiversity, public health, agriculture, and infrastructure, while evaluating current control measures including biological, chemical, and mechanical interventions. Emphasis is placed on the necessity of integrated weed management, restoration ecology, interdisciplinary research, and policy implementation to mitigate threats of invasive plant species and preserve the ecological integrity of urban landscapes.