Wildfire events have been impacting many parts of the United States. Of particular importance are the Wildland-Urban Interface (WUI) areas, where residential development exposes residents to increased risk from the threat of wildfire. However, evidence shows that WUI homeowners do not adequately mitigate risk through participation in programs such as Firewise USA®. In this investigation, we examined social-psychological factors that influence homeowners' intentions to adopt Firewise activities. Data were collected from a random sample of 1633 households in three wildfire-prone WUI areas of southern California. Structural equation modeling results illustrated that homeowners' perceived effectiveness of Firewise activities, along with their perceived risk of wildfire, significantly influenced their intentions to adopt suggested activities. We also found that respondents' past experience with wildfire and home attachment increased their intentions to adopt Firewise activities. Furthermore, the congruence between agency's and individuals' values (i.e., salient value similarity) increased homeowners' trust in agency management and information, and, subsequently, their perceptions of the effectiveness of wildfire risk mitigation activities. Alternately, past experience with wildfire diminished trust in agencies responsible for wildland fire mitigation. Our findings shed light on the ambiguities surrounding the role of past experience, risk perception, and place attachment in hazard preparedness. In addition to risk communication and promoting action effectiveness, our findings illustrate the importance of integrating cognitive heuristics and emotional bonds along with existing rational, evaluative models of decision-making to encourage homeowners' wildfire risk mitigation behavior.