A field study was conducted during Rabi, 2023-24 at Forage Research Block of APRI, Dr. Rajendra Prasad Central Agricultural University, Pusa, Bihar to evaluate the efficacy of few herbicides alone and in combination for weeds management in fodder oats seed production. Eleven treatments were tested on silty loam soils using RBD, replicated thrice. The tested treatments were: pre-emergence application (PE) of pendimethalin at 750 g/ha; oxyfluorfen at 200 g/ha PE; post-emergence application (PoE) of metsulfuron-methyl at 4 g/ha; 2,4-D at 500 g/ha PoE; pendimethalin at 750 g/ha PE followed by (fb) metsulfuron-methyl at 4 g/ha PoE; oxyfluorfen at 200 g/ha PE fb metsulfuron-methyl at 4 g/ha PoE; pendimethalin at 750 g/ha PE fb 2,4-D at 500 g/ha PoE; oxyfluorfen at 200 g/ha PE fb 2,4-D PoE at 500 g/ha; manual weeding twice at 20 and 40 days after seeding (DAS), hand hoeing at 20 DAS and weedy check. The Cynodon dactylon density was maximum with 38% relative density amongst the infested weed flora. The manual weeding twice at 20 and 40 DAS recorded the lowest weeds density and biomass and the highest fodder oats seed yield. Among the herbicides, pendimethalin at 750 g/ha PE fb metsulfuron-methyl at 4 g/ha PoE reduced the weed density and biomass and recorded the highest weed control efficiency, lowest weed index, highest nutrient uptake and crude protein yield and oats seed yield. The treatment oxyfluorfen at 200 g/ha PE fb metsulfuron-methyl at 4 g/ha PoE recorded the highest fodder oats straw yield.