Tourism research increasingly emphasizes the psychological mechanisms that foster responsible visitor behaviour at cultural destinations. This study investigates the role of destination image, place attachment, and effectiveness knowledge in shaping tourists' responsible behaviours in Shiraz, the cultural capital of Iran. Drawing on cognitive-affective theories of tourist experience, we conceptualize emotional engagement as a key mediating mechanism that translates visitors' cognitive appraisals and affective bonds into behavioural outcomes. Using survey data from domestic and international visitors to major heritage sites in Shiraz, we test a structural model linking destination image, place attachment, and knowledge to emotional engagement and, subsequently, to responsible behaviours such as rule compliance, heritage protection, and advocacy. The findings are expected to highlight the psychological pathways through which cognitive and emotional factors interact to promote sustainable visitor conduct. This study contributes to both tourism psychology and heritage management by offering insights into how cultural destinations can strengthen visitor engagement and foster behaviours that support long-term preservation.