Numerous studies have captured the nature of mind-wandering and how it changes across the lifespan; however, the influence of culture has been neglected. This study investigated the joint effects of culture and age in a large scale online questionnaire-based survey of 308 adults over 18 years of age, both in France and the United Kingdom. To capture a profile of thinking style, self-report measures of mind-wandering frequency, mindfulness, mood, rumination, self-reflection, future thinking, depressive symptoms, and cognitive failures were gathered. Findings revealed an earlier decrease in mind-wandering frequency for French speaking participants. Cultural effects were demonstrated on rumination and reflection rates across the life span, with in general more rumination and less reflection for English speakers. Overall, negatively toned thoughts were dominant for English compared to more expressive thoughts in general for French speakers. Confirmatory factor analyses featured different theoretical models to explain mind-wandering frequency in the French and British populations. This study provides the basis for further investigations of sociocultural influences on the eclectic phenomenon of mind-wandering.