Abstract: Weeds can be defined as unwanted and undesirable plants which are growing out of place. For an example, Eichhorniacrassipes (Waterhyacinth) is beautiful in floating gardens but can rapidly log waterways, cause to flood and making navigation impossible. Sri Lanka climate is suitable for weeds to adaptand to persist for survive. Their pattern of spread and adapting features are help to grasp cultivated lands. Sri Lanka has a poor record of managing weeds, largely due to inadequate mechanisms to deal with them early or prevent their entry through border protection. Recent stakeholder consultations identified insufficient funding for on-ground works and for research and the absence of a central coordination mechanism as major constraints. Control options are also limited (i.e. limited array of herbicides or biocontrol agents) and experience is also lacking in implementing large scale integrated weed management programs. To effectively tackle invasive species in Sri Lanka, a National Weed Strategy has been developed. This national framework aims to provide increased weed science education at tertiary level and increased training for government officials and farmers. It also aims provide a mechanism for efficient information sharing and effective multiple stakeholder cooperation and participation in managing weeds across landscapes. This review considers the major weeds in cultivated lands in Sri Lanka and it helps farmers to identify the weeds in their lands and to select weed management techniques according to the morphology of plant.