This study aimed to analyze the determinants of quality of life (QoL) in older people in three European countries (Portugal, Spain and Sweden). A sample of 7589 participants in waves 4 (2011) and 6 (2015) of the Survey on Health, Aging, and Retirement in Europe (SHARE) project, aged 50 and over and living in Portugal, Spain and Sweden, was included. The CASP-12 scale was used to measure QoL. A principal component analysis was performed to group preselected variables related to active and healthy ageing into the dimensions of health, social participation, and lifelong learning. A linear regression model was built using the change in CASP-12 scores over the 4-year follow-up as the dependent variable, including the interactions between country and each independent variable in the model. After four years, the average QoL increased in Portugal (difference = 0.8, p < 0.001), decreased in Spain (-0.8, p < 0.001), and remained constant in Sweden (0.1, p = 0.408). A significant country-participation component interaction (p = 0.039) was found. In Spain, a higher participation (beta = 0.031, p = 0.002) was related to a higher QoL improvement at 4 years, but not in Sweden or Portugal. Physical health and emotional components (beta = 0.099, p < 0.001), functional ability (beta = 0.044, p = 0.023), and cognitive and sensory ability (beta = 0.021, p = 0.026) were associated with QoL changes over time in all countries. The country-specific associations between health, social participation and QoL should be taken into account when developing public health policies to promote QoL among European older people.