The current study aims at dyeing cotton fabric with natural dye extracted from the leaves of parthenium hysterophorus. This would give scope for the utilization of unwanted terrestrial weeds. Parthenium hysterophorus is a commonly occurring annual herbaceous weed and aggressively colonized all over the place. This paper describes the extraction of dyes from their mature leaves and also their colorfastness properties. The pre-mordanting method was used for dyeing. Alum and tin chloride were used as mordants for the fixation of natural dye. The results showed eye-cooling shades and color fastness to light; washing, ironing, and crocking were found to be good to excellent. It was concluded that leaves of parthenium weed can be utilized for cost-effective cotton fabric dyeing with a variety of shades with average to good fastness properties. The problem of weed management will be rectified, and cost-effective dyed cotton fabric will be produced.