Resumen: Purpose: Encouraging travelers to create value that benefits firms is of great relevance for companies that operate in online contexts. The purpose of this study is to investigate, focusing on online travel agencies, how monetary promotions (i.e. economic incentives) and non-monetary promotions (i.e. draws and contests) conducted through social media enhance customers’ voluntary behaviors (i.e. suggestions, word of mouth, and social media interactions) that go beyond brand choice, which may provide benefit to firms. Design/methodology/approach: The research model draws on the social exchange theory, equity theory and the concept of perceived support – how customers perceive that companies care about their well-being. The authors collect information from 491 users of online travel agencies in Spain and test their hypotheses using partial least squares. They also evaluate the existence of indirect effects. Findings: Promotions developed by companies make customers more likely to perform, voluntarily, the helping behaviors of suggestions, word of mouth and social media interactions, through the influence of perceived support. Research limitations/implications: Use of a single survey to collect measures and restriction of the sample to Spanish-speaking travelers suggests caution in generalizing the results. Future research could investigate other company-initiated actions and other value-creating behaviors of travelers. Practical implications: Promotions help develop perceived support for customers, which leads to voluntary, valuable traveler behaviors. Promotions may be also sufficient to trigger some customer behaviors, such as word-of-mouth. Originality/value: Based on the social exchange and equity theories, this paper investigates the influence of social media promotions on customers’ voluntary behaviors via perceived support. Idioma: Inglés DOI: 10.1108/IJCHM-09-2017-0555 Año: 2019 Publicado en: INTERNATIONAL JOURNAL OF CONTEMPORARY HOSPITALITY MANAGEMENT 31, 2 (2019), 633-650 ISSN: 0959-6119 Factor impacto JCR: 5.667 (2019) Categ. JCR: HOSPITALITY, LEISURE, SPORT & TOURISM rank: 6 / 56 = 0.107 (2019) - Q1 - T1 Categ. JCR: MANAGEMENT rank: 20 / 226 = 0.088 (2019) - Q1 - T1 Factor impacto SCIMAGO: 2.203 - Tourism, Leisure and Hospitality Management (Q1)