The efficacy of Moringa oleifera seed lectin (WSMoL) as a metal remover in water and the effects of metals on its hemagglutinating and antibacterial activities were determined. Aqueous metal solutions were incubated with WSMoL for 8 h at 4°C and the concentrations of metals were determined using atomic absorption spectroscopy. Hemagglutination and antibacterial assays were conducted with WSMoL and lectin exposed or not to the metals. The removal efficiency of WSMoL was 49.00%, 53.21%, 71.45%, 55.42%, 69.88%, 62.14%, and 49.36% for Cd+2, Pb+2, Cu+2, Zn+2, Mg+2, Mn+2, and Al+3, respectively. WSMoL showed bacteriostatic and bactericidal activities against Escherichia coli and Salmonella enterica serovar Enteritidis. However, hemagglutinating and antibacterial activities were impaired after exposure to metals. In conclusion, WSMoL efficiently removed metals present in water but the interaction with metals impaired lectin carbohydrate-binding ability and antibacterial activity. This should be considered when properties of WSMoL other than metal removal are desired.