A field experiment was conducted to investigate the pea-weed competition which revealed a significant reduction in pea yield with increasing duration of crop weed competition. The weed density in the season-long weedy plot was found to increase up to 60 days after sowing (DAS) and decreased thereafter. However, the weed dry matter accumulation increased progressively with duration of the weedy period. Galinsoga parviflora was the most dominant weed species as indicated by higher values of summed dominance ratio (SDR) in all the treatments. Relative yield loss (RYL) in peas was predicted using logistic and Gompertz equations in weed and weed free set of treatments, to determine 21 to 48 DAS as the beginning and end of the critical period of pea-weed competition, respectively, which is equivalent to 260 to 510°C day growing degree days (GDD). The economic threshold (ET) for multi-weed species for pea crop was estimated to range between 2.15 to 20.91 plants/m2.