The purpose of this study is to examine and compare the effect of residents’ different dimensions of place attachment on their word-of-mouth (WOM) behavior in two cities: Sydney, Australia and Shanghai, China. A six-dimensional construct of place attachment is proposed based upon a detailed literature review: four attitudinal dimensions (place identity, place dependence, affective attachment, social bonding) and two interactional dimensions (place memory, place expectation) are proposed to reflect different aspects of a resident's attachment to a place. To test the dimensionality of place attachment and relationships between constructs, a survey was completed by 691 residents in the two targeted cities (361 from Sydney and 330 from Shanghai), and a structural equation modeling instrument was applied to analyze the data. The findings of the empirical study statistically support the dimensionality of place attachment proposed, and reveal that, in general, interactional dimensions of place attachment have an effect on WOM behavior. The results suggest that WOM behavior of residents of the two cities is influenced by different attitudinal dimensions of place attachment: Shanghai resident's place identity and social bonding predict one-to-one WOM, while Sydney residents’ affective attachment to Sydney influences their one-to-one WOM behavior. This analysis provides insights into residents’ psychology and behavior in different tourism destinations, as well as important inputs for the sustainable development of destination branding and C2C tourism communication in these two cities.