This research applies an integrated modelling approach, incorporating GIS, economic, and hydrologic modelling to evaluate the cost-effectiveness of wetland restoration scenarios in the 140 km2 Lynn River subwatershed in southern Ontario. Results from the Integrated Modelling for Watershed Evaluation of BMPs-Wetland (IMWEBs-Wetland) model show that under the historical climate scenario, wetland restoration decreases peak flow at the subwatershed outlet by an average 1.23 percent, and that individual wetland restoration locations retain local flows by an average 85 percent. The effects of low flow increases at the subwatershed outlet are not pronounced. The annual costs of wetland restoration were estimated with average opportunity costs, amortized restoration administration and engineering costs, and average inconvenience costs. The spatial distribution of wetland restoration cost-effectiveness shows locations that should be targeted for wetland restoration mainly due to their large contribution to peak flow decreases at the subwatershed outlet as well as low economic costs.