Each year wildfire affects communities in Canada, resulting in evacuations and, in some cases, loss of homes. Several Canadian wildfire management agencies have initiated mitigation programs aimed at reducing wildfire risk. Successful wildfire mitigation involves both community-level and homeowner action. This paper examines factors that influence wildfire mitigation by homeowners. We draw upon the general hazards and wildfire management literature to develop and test a theoretical model for homeowner wildfire mitigation that includes perceived risk, an evaluation of threat significance and the influence of perceived costs and benefits of mitigation. We used a mail survey to collect data from 1265 residents in six interface communities in the province of Alberta. Results showed a high level of completion for most mitigation activities. A structural equation model provided support for the hypothesis that the evaluation of threat involves weighing the negative effects of mitigation on homeowners' feelings of connectedness to nature and the cost of mitigation with the positive influences of fear, a sense of responsibility and perceived effectiveness of mitigation. Considering the total effects, threat assessment had the greatest effect on mitigation by homeowners, followed by perceived effectiveness of mitigation in reducing damage and not having financial resources for mitigation.