An attempt was made to assess the awareness and knowledge level of urban residents on Parthenium hysterophorus, an obnoxious invasive alien weed. The questionnaire survey was conducted in urban council limit of Vavuniya district. To measure the level of awareness and knowledge of the respondents, a score was assigned to different knowledge dimensions such as knowledge on invasion, morphological features, life – cycle and mode of dispersion, adverse impacts, control measures and existing government law and regulation of Parthenium weed.  The correlation between knowledge dimensions and the age, gender and educational status of the people was statistically evaluated using Pearson correlation coefficient analysis. Above 65% of the respondents pose good knowledge on the morphological characters and habitat of Parthenium weed. Majority of the respondents were aware about the Parthenium dispersion, however, the knowledge of using integrated methods to eradicate Parthenium was relatively lower. Manual method of controlling was well known than the other methods. The average scores for knowledge on life cycle and dispersal, adverse effects and control measures of Parthenium hysterophorus are relatively low. Knowledge on respective Government laws and regulations and morphological identification are in moderate level while knowledge on invasion is good. According to the results, the knowledge on invasion and identification shows strong positive correlation with age. Knowledge on invasion shows strong positive correlation with the educational status.  Other knowledge parameters do not show a significant relationship with age, gender and educational status