Purpose: The long‐term effects of sociodemographic and health characteristics on television viewing (TV) time changes have not been identified in adulthood. We aimed to examine the modifiable and non‐modifiable determinants of changes in TV‐time in young adults over 10 years.Methods: Participants (N = 2929) aged 24‐39 years were recruited between 2001 and 2011 from the Cardiovascular Risk in Young Finns Study. Data were collected using questionnaires and a medical examination. The determinants of changes in TV‐time were estimated using latent growth modeling for men and women separately.Results: For men, inverse associations with initial levels of TV‐time were observed for students becoming employed and already has children, and direct associations were observed for both those who stayed a smoker and those who stayed overweight/obese. Increasing attention to health habits was inversely associated with a slope of TV‐time, whereas age and becoming unemployed were positively associated with the slope of TV‐time. For women, inverse associations with the levels of TV‐time were found for age, staying in non‐manual work, and paying consistently high and increasing attention to health habits, and direct associations were found for staying unemployed, smoking and overweight/obese, and becoming employed, single and non‐smoking. Increasing physical activity, becoming employed, motherhood, and normal weight were inversely associated with the slope of TV‐time, whereas age and staying in non‐manual work were positively associated with the slope of TV‐time.Conclusions: This suggests several gender‐specific determinants of changes in TV‐time that can help identify potential targets for interventions to prevent excessive TV‐time in adulthood.