Phytosociological studies of the weed flora of tea plantations in south India were carried out to generate information that could assist in identifying important and recalcitrant weeds during different seasons and in various situations which in turn should help in formulating effective measures for their control. One hundred and twelve weed species were found to occur in the tea fields of south India during the rainy seasons (June to December). The weed flora during the rainy season was dominated by Drymaria cordata, Bidens pilosa, Ageratum conyzoides, Crassocephalum crepidioides and Spermacoce ocymoides. During the dry season (January to March) only 34 weed species were recorded and the dominant weed species were Conyza leucantha, Conyza bonariensis, Ageratum conyzoides, Panicum repens and Paspalum conjugatum. Tea fields adjacent to human habitats favoured the growth of Drymaria cordata, Amaranthus viridis, A. spinosus, Rorippa dubia and Persicaria barbata. Panicum repens, Paspalum conjugatum, Axonopus compressus and Cyperus rotundus were the dominant weeds in tea fields adjoining water sources. Tea fields bordering forest boundaries had Persicaria chinensis, Chromolaena odorata, Pteridium aquilinum, Mikania cordata and Urena lobata