A field experiment was conducted in the summer of 2021 at the Crop Research Farm of the College of Post-Graduate Studies in Agricultural Sciences, Meghalaya, to determine the extent of yield loss in rice with different periods of weed interference. Twelve weed control timings were used to identify critical periods of weed competition in transplanted rice. Gompertz and Logistic equations were fitted to yield data in response to increasing periods of weed control and weed interference, respectively. The results showed that critical weed-free periods to achieve 95% of weed-free yield ranged from 11 – 57 days after transplanting. Grain yield obtained from a weed control period up to 60 days after transplanting and a weed competition period of 12 days after transplanting were statistically at par with the no-weed competition until harvest plot. Despite registering the highest yields, the plots that were kept weed-free till harvest were less profitable due to the incurred weeding costs. The identification of the critical crop-weed competition period will facilitate improved decision-making regarding the timing of weed control.