Field experiment was conducted during the winter seasons of 2014-15 and 2015-16 to study the effect of sole and sequential application of herbicides on weed growth and productivity of sunflower (Helianthus annuus L.). Echinochloa colona, Digitaria sanguinalis and Dactyloctenium aegyptium among grasses; Cyperus rotundus and Cyperus difformis among sedges and Cleome viscosa, Euphorbia hirta and Borreria hispida among broad-leaved weeds, were predominant throughout the cropping period. Weed competition resulted in 31.3% yield loss in sunflower. Sequential application of oxyfluorfen 250 g/ha at 3 days after seeding (DAS) followed by (fb) quizalofop-ethyl 50 g/ha at 20 DAS resulted in the lowest weed density (41/m2), total weed biomass (19.37 g/m2), maximum nutrient uptake, yield (2.1 t/ ha) and benefit:cost ratio (1.82).