Nitrous　oxide　(N2O),　a　potent　greenhouse　gas,　significantly　contributes　to　the　carbon　footprint　of　wastewater　treatment　plants　(WWTPs)　and　contributes　significantly　to　global　climate　change　and　to　the　deterioration　of　the　natural　environment.　Our　understanding　of　N2O　generation　mechanisms　has　significantly　improved　in　the　last　decade,　but　the　development　of　effective　N2O　emission　mitigation　strategies　has　lagged　owing　to　the　complexity　of　parameter　regulation,　substandard　monitoring　activities,　and　inadequate　policy　criteria.　Based　on　critically　screened　published　studies　on　N2O　control　in　full-scale　WWTPs,　this　review　elucidates　N2O　generation　pathway　identifications　and　emission　mechanisms　and　summarizes　the　impact　of　N2O　on　the　total　carbon　footprint　of　WWTPs.　In　particular,　a　linear　relationship　was　established　between　N2O　emission　factors　and　total　nitrogen　removal　efficiencies　in　WWTPs　located　in　China.　Promising　N2O　mitigation　options　were　proposed,　which　focus　on　optimizing　operating　conditions　and　implementation　of　innovative　treatment　processes.　Furthermore,　the　sustainable　operation　of　WWTPs　has　been　anticipated　to　convert　WWTPs　into　absolute　greenhouse　gas　reducers　as　a　result　of　the　refinement　and　improvement　of　on-site　monitoring　activities,　mitigation　mechanisms,　regu-lation　of　operational　parameters,　modeling,　and　policies.