This study used the dominant cognitive-based theory of planned behaviour (TPB) complemented by the affection-based attachment theory (AT) to investigate factors influencing local residents’ conservation intentions. Thus, in addition to TPB’s variables, such as attitudes towards conservation, perceived social pressure and perceived control over conservation, the study considered the effects of heritage affection on conservation intentions. Cross-sectional questionnaire-based data gathered from the three historic towns of Zanzibar Stone Town, Kilwa Kivinje and Pangani in Tanzania were analysed using Structural Equation Modelling. The TPB’s variables and heritage affection all showed a positive and significant correlation with conservation intention. The empirical data therefore supported using the TPB, complemented by the AT, to explain engagement in conservation in the built heritage setting. The study concludes that conservation intention is best viewed as a mixture of cognitive and affective factors. Theoretical and managerial implications as well as suggestions for future studies are provided.