BackgroundSport participation is an important component of a healthy lifestyle and is known to be more common among privileged individuals. However, few studies examined socio-demographic patterns of participation by type of activity. This study aims at quantifying socio-economic inequalities in sport participation by sport type, and to analyse their trend over 15 years.MethodsWe used 2005–2019 data from the Bus Santé study, a yearly population-based cross-sectional survey of Geneva adults. Sport participation was defined as reporting at least one sporting activity over the previous week; educational level, household income and occupational position were used as indicators of socio-economic position. Socio-economic inequalities in sport participation, and their trend over time, were examined using the relative and slope indexes of inequality (RII/SII).ResultsOut of 7769 participants (50.8% women, mean age 46 years old), 60% participated in a sporting activity. Results showed that the higher the socioeconomic circumstances, the higher the sport participation (RII = 1.78; 95% Confidence Interval (CI): 1.64–1.92; SII = 0.33; 95%CI: 0.29–0.37 for education). Relative inequalities varied per sport e.g., 0.68 (95%CI: 0.44–1.07) for football and 4.25 (95%CI: 2.68–6.75) for tennis/badminton for education. Yearly absolute inequalities in sport participation tended to increase between 2005 and 2019 for household income, especially among women and older adults.ConclusionsWe observed strong socio-economic inequalities in sport participation in Geneva, with different magnitude depending on the sport type. These inequalities seemed to increase over the 2005–2019 period. Our results call for tailored measures to promote the participation of socially disadvantaged populations in sporting activities.