Resumen: The aim of this study was to assess the mediating role of affects between mind-wandering and happiness. The study was conducted with a sample comprising 270 university students-133 men (49.26%) and 137 women (50.74%)-who filled out the Mind-Wandering Questionnaire (MWQ), the Positive and Negative Affect Questionnaire (PANAS), and the SHS subjective happiness scale. Mind-wandering was found to be negatively correlated with happiness and positive effects. Higher mind-wandering-related scores went hand in hand with scores related to both lower happiness and positive affects. Approximately half the participants yielded low mind-wandering and negative affect scores and above-average happiness and positive affects scores. In addition, one in four scored above average in terms of mind-wandering and low in terms of happiness and positive effects. Finally, the mediating role played by affects was examined. It can be concluded that although in principle mind-wandering has no direct effect on happiness, some influence can be attested when affects, both positive and negative, are taken into consideration. Idioma: Inglés DOI: 10.3390/su12125139 Año: 2020 Publicado en: Sustainability (Switzerland) 12, 12 (2020), 5139 [9 pp.] ISSN: 2071-1050 Factor impacto JCR: 3.251 (2020) Categ. JCR: ENVIRONMENTAL SCIENCES rank: 124 / 273 = 0.454 (2020) - Q2 - T2 Categ. JCR: ENVIRONMENTAL STUDIES rank: 60 / 125 = 0.48 (2020) - Q2 - T2 Categ. JCR: GREEN & SUSTAINABLE SCIENCE & TECHNOLOGY rank: 30 / 44 = 0.682 (2020) - Q3 - T3 Categ. JCR: GREEN & SUSTAINABLE SCIENCE & TECHNOLOGY rank: 6 / 9 = 0.667 (2020) - Q3 - T3 Factor impacto SCIMAGO: 0.611 - Energy Engineering and Power Technology (Q1) - Environmental Science (miscellaneous) (Q1) - Renewable Energy, Sustainability and the Environment (Q1) - Management, Monitoring, Policy and Law (Q1) - Geography, Planning and Development (Q1)