Abstract: Butterflies are among the most attractive and colourful organisms on the planet, with a high aesthetic value. They are bio-indicators of the environment and ecosystem. Adult butterflies pollinate many plant species and their young ones (larva) feed on crop plants and weeds. The presence of weed-eating butterflies in agro-ecosystems has made a significant contribution to natural weed suppression, thereby reducing the consumption of herbicides. In this context, an attempt was made to survey for butterflies in the coastal agro-ecosystem of selected localities in Cuddalore district, Tamil Nadu during winter season 2021-22. A butterfly survey was done twice a month in the study area and the larval weed host plants were also documented. The results of the study showed that a total of 188 weed suppressing butterflies, which comprised six species and five genera, were observed from the study area under the families Pieridae, Nymphalidae, Lycaenidae and Hesperiidae of the Order Lepidoptera. Among the species of weed suppressing butterflies, Hypolimnas misippus was found maximum in the survey, followed by H. bolina of Nymphalidae family. The important weed hosts found in the study area were Cleome viscosa, Portulaca oleracea, Abutilon indicum, Corchorus depressus, Achyranthes aspera and Amaranthus viridis. The diversity of weed suppressing butterflies in the study area of coastal district offers a possible exploitation and scope in weed management in agro-ecosystems naturally. [Chandrasekaran, K. et al. (2022). Futuristic scope of weed suppressing butterflies in coastal agricultural ecosystem. Crop Research, 57 (5/6).]