ABSTRACT Global warming delays the harvest of kharif crops, which delay the subsequent sowing of Indian mustard, especially in northwestern India and also causes dry winters that exacerbate challenges for the timely sowing of rabi-crops. To check this, a field experiment was conducted during the Rabi-seasons of 2018–19 and 2019–20 to assess the influence of sowing dates, irrigation, and fertilizer levels under late-sown conditions. A split-plot design was used with two sowing dates, two irrigation levels and four fertilizer levels (87.5%, 100%, 112.5% and 125% RDF; Recommended-fertilizers-dose). Crop sown in the 4th week of November significantly reduced seed (46.79 and 38.77%) and stover yield (43.72 and 41.62%) as compared to the 2nd week of November sowing during 2018–19 and 2019–20, respectively. Uptake of NPK by seed and stover was higher with the 2nd week of November sowing. The 2nd week of November sowing resulted in significant increase in water productivity by 63.72% and Benefit cost ratio (B:C) by 75.45% over the 4th week of November sowing. Irrigation at flowering stage increased the seed yield, water productivity and B:C by 11.94%, 1.72% and 9.17%, respectively, as compared to No post-sown irrigation. The biological yield of the Indian mustard increased with every increase in fertilizer doses but the response was significant up to 112.5% RDF (90 kg N, 33.75 kg P2O5 and 22.5 kg K2O ha−1). Application of 112.5% RDF increased the seed, stover yield, water productivity and B:C by 16.17%, 9.29%, 15.66% and 11.27%, respectively, over 87.5% RDF.