Weed suppression benefits of cover crops (CCs) have long been recognized; however, the specific ability of CCs to suppress highly epidemic Amaranthus spp. (Palmer amaranth (Amaranthus palmeri S. Watson), redroot pigweed (Amaranthus retroflexus L.), smooth pigweed (Amaranthus hybridus L.), and waterhemp [Amaranthus tuberculatus (Moq.) Sauer]) has not been widely discussed. The objective of this meta-analysis was to evaluate the implications of CC management decisions (CC type, planting and termination methods, residue fate after termination, and in-season weed management plan) on Amaranthus spp. weed density (ASWD) and Amaranthus spp. weed biomass (ASWB) compared to no CC (NCC) in temperate regions including US and Canada. We found 41 studies conducted across US and Canada and extracted 595 paired observations. The results indicate that CCs reduced the ASWD by 58% in the early- [0–4 weeks after crop planting (WAP)], by 48% in the mid- (5–8 WAP) and by 44% in the late- (>8 WAP) season. Similarly, CCs reduced ASWB by 59%, 55%, and 37% in the early-, mid-, and late-season, respectively. Meta-regression analysis showed CCs terminated within 2.5 weeks of crop planting reduced ASWD by ≥50%. Cover crop biomass required to reduce ASWD and ASWB by 50% was 4,079 kg ha–1 for ASWD and 5,352 kg ha–1 for ASWB. Among CC types, grasses and mixtures reduced ASWD by 60% and 77% in early-, 53% and 59% in mid-, and 44% and 47% in late-season. Legume CCs were effective only during the early-season (47% ASWD reduction) while brassicas did not affect ASWD. Cover crop residues remaining on the soil surface were more effective for reducing ASWD than incorporation. Cover crops did not affect ASWD or ASWB compared to NCC when herbicides were used for in-season weed management. In general, CCs were found to reduce ASWD, and ASWB, therefore can be used as an effective tool for integrated management of Amaranthus spp.