Amongst all biotic factors, weeds pose the most serious threat to successful cotton production. Adoption of conservation agriculture, the evolution of herbicide-resistant weed populations, and the absence of any new herbicide chemistry are allowing weeds to become more destructive and uncontrollable. It is important now to investigate cultural practices (non-chemical) to reduce the pressure on herbicides. Trials were conducted at the Gatton Research Farm of University of Queensland during 2015/16 and 2016/17 to assess the implications of narrow row-spacing (50 cm) in managing weeds in glyphosate-tolerant cotton at different weed-infestation intervals [0, 21, 42, 63, 84 and 154 days after planting (DAP)]. Results revealed that narrow (50 cm) row-spacing (at the same density of planting) was not only beneficial in suppressing weed growth (55% lower) and achieving greater lint yield (26% more) but also made the cotton plants more competitive in the early weed-crop interference compared with wide (100 cm) row-spacing. Consequently, the weed-crop competition period (CWIP) was shorter (42 days after emergence) in narrow row-spaced cotton when compared with wide row-spaced cotton (154 days after emergence). The use of this technology will reduce the reliance on herbicides, which in turn will decrease the development of future herbicide-resistant weed populations.