The present study was conducted at MPUAT, Udaipur, India, during two consecutive Kharif (rainy season) of 2016 and 2017 to assess the effect of weed management treatments and phosphorus levels on weeds; groundnut growth, yield, quality and probability of groundnut cultivation. A split-plot design was used with six weed management treatments i.e., weedy check, weed free up to 60 days after seeding (DAS), pendimethalin 750 g/ha pre-emergence application (PE), oxyfluorfen 125 g/ha PE, imazethapyr 100 g/ha post-mergence application at 15 DAS (PoE) and quizalofop-ethyl 50 g/ha PoE at 15 DAS as main plots, and five phosphorus levels, viz. 0, 20, 40,60 and 80 kg P/ha as sub-plots with three replications. The lowest density of Cyperus rotundus and Echinochloa colona was recorded with imazethapyr and quizalofop-ethyl, respectively. The lowest density of other narrow-leaved weeds at 30, 60 DAS and harvest was registered with pendimethalin, quizalofop-ethyl and imazethapyr, respectively. Weed free up to 60 DAS was the most effective in managing weeds and increasing groundnut yield. Amongst herbicide treatments, imazethapyr 100 g/ha PoE recorded significantly minimum weed index, weed persistence index, crop resistance index, and the highest values of growth and yield parameters, and N, P and K uptake. Application of 60 kg P/ha has registered significantly the highest plant height, dry matter accumulation, 100 kernels weight and pod yield (1.76 t/ha), biological yield (4.86 t/ha) and also the harvest index (35.83%). Significantly higher protein and oil content were noticed when the crop was fertilized with 40 kg P/ha. The total N, P and K uptake by crop were significantly higher by 87.83, 92.10 and 60.97% over control, respectively with 80 kg P/ha.