Article An application of Tetraclass model for evaluating ecotourism service quality in Vietnam Vo Thi Ngoc Thuy Faculty of Business Administration, University of Economics and Law, Vietnam National University, Ho Chi Minh city, Vietnam Ho Huy Tuu Economics Faculty, Nha Trang University, Vietnam Sylvie Llosa Aix-Marseille Graduate School of Management, Aix-Marseille University, France Hoang Doan Phuong Thao Faculty of Business Administration, University of Economics and Law, Vietnam National University, Ho Chi Minh city, Vietnam Abstract This study extends SERVQUAL and ECOSERV models to include interaction and experience attributes in an ecotourism context and to identify how ecotourism service attributes can affect Vietnamese ecotourist satis- faction and dissatisfaction using Tetraclass approach. This study uses a combination of both qualitative and quantitative methods. The results show 47 ecotourism service quality attributes belonging to 10 dimensions and four categories as Basic, Key, Plus, and Secondary. The findings also indicate the 10 most important attributes contributing to ecotourist satisfaction/dissatisfaction and confirm the complex relationships of ecotourism service attributes on ecotourist satisfaction/dissatisfaction. While ecotourism has become one of the most important subsectors in the tourism industry, understanding ecotourists’ evaluations and improving their sat- isfaction with ecotourism is still mostly underexplored, in particular, in the context of a developing country like Vietnam. Therefore, this study helps managers understand effective ways to improve customers’ satisfaction and eliminate their dissatisfaction. However, it ignores customers’ affective moods. Thus, future studies could benefit to include these aspects to gain a better understanding about the phenomenon. Keywords Tetraclass model, satisfaction and dissatisfaction, asymmetrical effects, ecotourism, Vietnam Introduction There is a noticeable shift from mass tourism to sustain- able tourism services, in which ecotourism has received considerable attention by both tourism researchers and managers (Cini et al., 2017; Pornprasit and Rurkkhum, 2019; Shi et al., 2019). Most previous studies about ecotourism focus its impact on the environment, local economy and community life quality (e.g. Jones, 2005; Shi et al., 2019; Tran and Walter, 2014), ecotourist motivation and experience (e.g. Chan and Baum, 2007a, 2007b; Chiu et al., 2014; Zhang and Lei, 2012), or exploring ecotourist segmentations (e.g. Hvenegaard, 2002). Only a few studies focus on eco- tourism service attributes (e.g. Khan, 2003; Lu and Corresponding author: Vo Thi Ngoc Thuy, Faculty of Business Administration, University of Economics and Law, Vietnam National University, KP 3, Linh Xuan Ward, Thu Duc District, Ho Chi Minh City, Vietnam. Email: thuyvtn@uel.edu.vn Tourism and Hospitality Research 0(0) 1–17 ! The Author(s) 2019 Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/1467358419867741 journals.sagepub.com/home/thr